Grade 6 Glossary

Unit 8 Lesson 2, Unit 8 Lesson 3

The word base can also refer to a face of a polyhedron.

A prism has two identical bases that are parallel. A pyramid has one base.

A prism or pyramid is named for the shape of its base.

A pentagonal prism and hexagonal pyramid with bases labeled.

box plot

Unit 8 Lesson 7

A box plot is a way to represent data on a number line. The data is divided into four sections. The sides of the box represent the first and third quartiles. A line inside the box represents the median. Lines outside the box connect to the minimum and maximum values.

For example, this box plot shows a data set with a minimum of 2 and a maximum of 15. The median is 6, the first quartile is 5, and the third quartile is 10.

A box plot showing a data set with a minimum of 2 and a maximum of 15. The median is 6, the first quartile is 5, and the third quartile is 10.

center

The center of a set of numerical data is a value in the middle of the distribution. It represents a typical value for the data set.

For example, the center of this distribution of cat weights is between 4.5 and 5 kilograms.

A dot plot for "cat weights in kilograms". The numbers 2 through 12 are indicated. The data are as follows: 3 kilograms, 2 dots. 3.5 kilograms, 3 dots. 4 kilograms, 4 dots. 4.5 kilograms, 5 dots. 5 kilograms, 5 dots. 5.5 kilograms, 4 dots. 6 kilograms, 3 dots. 6.5 kilograms, 3 dots. 7 kilograms, 1 dot.

chance experiment

Unit 5 Lesson 11, Unit 5 Lesson 12, Unit 5 Lesson 13

A chance experiment is something you can do over and over again, and you don’t know what will happen each time.

For example, each time you spin the spinner, it could land on red, yellow, blue, or green.

circle

A circle is made out of all the points that are the same distance from a given point.

For example, every point on this circle is 5 cm away from point $A$ , which is the center of the circle.

A circle with the center at point A and five lines going from the A to the edge labeled B, C, D, E, F. All lines are 5 cm long.

circumference

Unit 5 Lesson 11, Unit 5 Lesson 12, Unit 5 Lesson 13

The circumference of a circle is the distance around the circle. If you imagine the circle as a piece of string, it is the length of the string. If the circle has radius $r$ then the circumference is $2 π r$ .

The circumference of a circle of radius 3 is $2 \cdot π \cdot 3 = 6 π$ , which is about 18.85.

coefficient

Unit 4 Lesson 2, Unit 4 Lesson 3, Unit 4 Lesson 4, Unit 4 Lesson 5

A coefficient is a number that is multiplied by a variable.

For example, in the expression $3 x + 5$ , the coefficient of $x$ is 3. In the expression $y + 5$ , the coefficient of $y$ is 1, because $y = 1 \cdot y$ .

compose

Unit 1 Lesson 2

Compose means “put together.” We use the word compose to describe putting more than one figure together to make a new shape.

Two half circles with a rectangle in the middle. They are not connected in the first picture but are in the second picture.

constant of proportionality

Unit 5 Lesson 1, Unit 5 Lesson 2, Unit 5 Lesson 3

In a proportional relationship, the values for one quantity are each multiplied by the same number to get the values for the other quantity. This number is called the constant of proportionality.

In this example, the constant of proportionality is $3$ , because $2 \cdot 3 = 6$ , $3 \cdot 3 = 9$ , and $5 \cdot 3 = 15$ . This means that there are 3 apples for every 1 orange in the fruit salad.

number of oranges	number of apples
$2$	$6$
$3$	$9$
$5$	$15$

constant term

Unit 4 Lesson 18, Unit 5 Lesson 7, Unit 5 Lesson 8, Unit 5 Lesson 9, Unit 5 Lesson 20

In an expression like $5 x + 2$ , the number $2$ is called the constant term because it doesn’t change when $x$ changes.

In the expression $7 x + 9$ , $9$ is the constant term.
In the expression $5 x + (- 8)$ , $- 8$ is the constant term.
In the expression $12 - 4 x$ , $12$ is the constant term.

coordinate plane

The coordinate plane is a system for telling where points are. For example, point $R$ is located at $(3, 2)$ on the coordinate plane, because it is three units to the right and two units up.

A picture of a coordinate plane with a point (R) plotted at (3, 2).

cubed

Unit 4 Lesson 11, Unit 4 Lesson 12

We use the word cubed to mean “to the third power.” This is because a cube with side length $s$ has a volume of $s \cdot s \cdot s$ , or $s^{3}$ .

decompose

Unit 1 Lesson 2, Unit 1 Lesson 3

Decompose means “take apart.” We use the word decompose to describe taking a figure apart to make more than one new shape.

Two half circles with a rectangle in the middle all connected and then in the second picture they are split apart.

dependent variable

Unit 4 Lesson 17

The dependent variable is the result of a calculation.

For example, a boat travels at a constant speed of 25 miles per hour. The equation $d = 25 t$ describes the relationship between the boat’s distance and time. The dependent variable is the distance traveled, because $d$ is the result of multiplying 25 by $t$ .

A graph of 10 points plotted in the coordinate plane with the origin labeled "O". The horizontal t axis is labeled "time in hours". The numbers 0 through 10, in increments of 2, are indicated, and there are vertical gridlines midway between. The vertical axis is labeled "distance traveled in miles". The numbers 0 through 250, in increments of 25, are indicated, and there are horizontal gridlines midway between. The data are as follows: 1 comma 25. 2 comma 50. 3 comma 75. 4 comma 100. 5 comma 125. 6 comma 150. 7 comma 175. 8 comma 200. 9 comma 225. 10 comma 250.

deposit

Unit 7 Lesson 8, Unit 7 Lesson 9, Unit 7 Lesson 10

When you put money into an account, it is called a deposit.

For example, a person added $60 to their bank account. Before the deposit, they had $435. After the deposit, they had $495, because $435 + 60 = 495$ .

diameter

Unit 5 Lesson 11, Unit 5 Lesson 12, Unit 5 Lesson 13

A diameter is a line segment that goes from one edge of a circle to the other and passes through the center. A diameter can go in any direction. Every diameter of the circle is the same length. We also use the word diameter to mean the length of this segment.

A circle with a line going through the center and across the circle labeled diameter.

difference

Unit 8 Lesson 1, Unit 8 Lesson 2, Unit 8 Lesson 3

The result when one number is subtracted from another.

distribution

The distribution tells how many times each value occurs in a data set. For example, in the data set blue, blue, green, blue, orange, the distribution is 3 blues, 1 green, and 1 orange.

Here is a dot plot that shows the distribution for the data set 6, 10, 7, 35, 7, 36, 32, 10, 7, 35.

A dot plot for "dog weights in kilograms". The numbers 5 through 40, in increments of 5, are indicated. The data are as follows: 6 kilograms, 1 dot. 7 kilograms, 3 dots. 10 kilograms, 2 dots. 32 kilograms, 1 dot. 35 kilograms, 2 dots. 36 kilograms, 1 dot.

double number line diagram

Unit 2 Lesson 4, Unit 2 Lesson 5, Unit 2 Lesson 6

A double number line diagram uses a pair of parallel number lines to represent equivalent ratios. The locations of the tick marks match on both number lines. The tick marks labeled 0 line up, but the other numbers are usually different.

A double number line for teaspoons of red paint: 0, 3, 6, 9, 12 and teaspoons of yellow paint: 0, 5, 10, 15, 20.

edge

Unit 1 Lesson 9

Each straight side of a polygon is called an edge.

For example, the edges of this polygon are segments $\overset{―}{A B}$ , $\overset{―}{B C}$ , $\overset{―}{C D}$ , $\overset{―}{D E}$ , and $\overset{―}{E A}$ .

An enclosed polygon of an irregular shape labeled A, B, C, D, E.

equivalent expressions

Unit 4 Lesson 8, Unit 4 Lesson 9, Unit 4 Lesson 10

Equivalent expressions are always equal to each other. If the expressions have variables, they are equal whenever the same value is used for the variable in each expression.

For example, $3 x + 4 x$ is equivalent to $5 x + 2 x$ . No matter what value we use for $x$ , these expressions are always equal. When $x = 3$ , both expressions equal 21. When $x = 10$ , both expressions equal 70.

equivalent ratios

Unit 2 Lesson 3

Two ratios are equivalent if you can multiply each of the numbers in the first ratio by the same factor to get the numbers in the second ratio. For example, $8 : 6$ is equivalent to $4 : 3$ , because $8 \cdot \frac{1}{2} = 4$ and $6 \cdot \frac{1}{2} = 3$ .

A recipe for lemonade says to use 8 cups of water and 6 lemons. If we use 4 cups of water and 3 lemons, it will make half as much lemonade. Both recipes taste the same, because $8 : 6$ and $4 : 3$ are equivalent ratios.

cups of water	number of lemons
$8$	$6$
$4$	$3$

event

Unit 4 Lesson 11, Unit 4 Lesson 12

An event is a set of one or more outcomes in a chance experiment. For example, if we roll a number cube, there are six possible outcomes.

The six faces of a dice - 1 dot, 2 dots, 3 dots, 4 dots, 5 dots, 6 dots.

Examples of events are “rolling a number less than 3,” “rolling an even number,” or “rolling a 5.”

exponent

In expressions like $5^{3}$ and $8^{2}$ , the $3$ and the $2$ are called exponents. They tell you how many factors to multiply.

For example, $5^{3}$ = $5 \cdot 5 \cdot 5$ , and $8^{2} = 8 \cdot 8$ .

face

Unit 1 Lesson 10, Unit 1 Lesson 11, Unit 1 Lesson 12

Each flat side of a polyhedron is called a face. For example, a cube has 6 faces, and they are all squares.

factor

Unit 8 Lesson 1, Unit 8 Lesson 2, Unit 8 Lesson 3

A factor of a whole number is a whole number that divides it evenly without a remainder.

For example, 1, 2, 3, 4, 6, and 12 are all factors of 12, but 5 is not a factor.

frequency

The frequency of a data value is how many times it occurs in the data set.

For example, there were 20 dogs in a park. The table shows the frequency of each color.

color	frequency
white	$4$
brown	$7$
black	$3$
multi-color	$6$

height (of a parallelogram or triangle)

Unit 1 Lesson 5

The height is the shortest distance from the base of the shape to the opposite side (for a parallelogram) or opposite vertex (for a triangle).

We can show the height in more than one place, but it will always be perpendicular to the chosen base.

Two parallelograms with the base and height labeled.

histogram

Unit 8 Lesson 3

A histogram is a way to represent data on a number line. Data values are grouped by ranges. The height of the bar shows how many data values are in that group.

This histogram shows there were 10 people who earned 2 or 3 tickets. We can’t tell how many of them earned 2 tickets or how many earned 3. Each bar includes the left-end value but not the right-end value. (There were 5 people who earned 0 or 1 tickets and 13 people who earned 6 or 7 tickets.)

A histogram with number of tickets on the horizontal axis ranging from 0 to 10 in increments of 2. The vertical axis is from 0 to 14 in increments of 2.

independent variable

Unit 4 Lesson 17, Unit 4 Lesson 18

The independent variable is used to calculate the value of another variable.

For example, a boat travels at a constant speed of 25 miles per hour. The equation $d = 25 t$ describes the relationship between the boat’s distance and time. The independent variable is time, because $t$ is multiplied by 25 to get $d$ .

interquartile range (IQR)

Unit 4 Lesson 3, Unit 8 Lesson 7, Unit 8 Lesson 11, Unit 8 Lesson 12

The interquartile range is one way to measure how spread out a data set is. We sometimes call this the IQR. To find the interquartile range we subtract the first quartile from the third quartile.

22	29	30	31	32	43	44	45	50	50	59
		Q1			Q2			Q3

For example, the IQR of this data set is 20 because $50 - 30 = 20$ .

long division

Unit 3 Lesson 18, Unit 3 Lesson 19, Unit 3 Lesson 20, Unit 6 Lesson 2

Long division is a way to show the steps for dividing numbers in decimal form. It finds the quotient one digit at a time, from left to right.

For example, here is the long division for $57 \div 4$ .

$\begin{array}{r} 14.25 \\ 4 57.00 \\ \underset{―}{- 4} \\ 17 \\ \underset{―}{- 16} \\ 10 \\ \underset{―}{- 8} \\ 20 \\ \underset{―}{- 20} \\ 0 \end{array}$

mean

Unit 8 Lesson 4, Unit 8 Lesson 5, Unit 8 Lesson 8, Unit 8 Lesson 9, Unit 8 Lesson 10

The mean is one way to measure the center of a data set. We can think of it as a balance point. For example, for the data set 7, 9, 12, 13, 14, the mean is 11.

A number line from 7 to 22. The data set is plotted and the mean is 11.

To find the mean, add up all the numbers in the data set. Then, divide by how many numbers there are. $7 + 9 + 12 + 13 + 14 = 55$ and $55 \div 5 = 11$ .

mean absolute deviation (MAD)

Unit 8 Lesson 5, Unit 8 Lesson 8, Unit 8 Lesson 9, Unit 8 Lesson 10

The mean absolute deviation is one way to measure how spread out a data set is. Sometimes we call this the MAD. For example, for the data set 7, 9, 12, 13, 14, the MAD is 2.4. This tells us that these travel times are typically 2.4 minutes away from the mean, which is 11.

To find the MAD, add up the distance between each data point and the mean. Then, divide by how many numbers there are. $4 + 2 + 1 + 2 + 3 = 12$ and $12 \div 5 = 2.4$ .

measure of center

Unit 8 Lesson 4, Unit 8 Lesson 5

A measure of center is a value that seems typical for a data distribution.

Mean and median are both measures of center.

measurement error

Unit 6 Lesson 9, Unit 6 Lesson 10, Unit 6 Lesson 11

Measurement error is the positive difference between a measured amount and the actual amount.

For example, Diego measures a line segment and gets 5.3 cm. The actual length of the segment is really 5.32 cm. The measurement error is 0.02 cm, because $5.32 - 5.3 = 0.02$ .

median

Unit 8 Lesson 6, Unit 8 Lesson 7, Unit 8 Lesson 8, Unit 8 Lesson 9, Unit 8 Lesson 10

The median is one way to measure the center of a data set. It is the middle number when the data set is listed in order.

For the data set 7, 9, 12, 13, 14, the median is 12.

For the data set 3, 5, 6, 8, 11, 12, there are two numbers in the middle. The median is the average of these two numbers. $6 + 8 = 14$ and $14 \div 2 = 7$ .

meters per second

Unit 2 Lesson 6, Unit 2 Lesson 7

Meters per second is a unit for measuring speed. It tells how many meters an object goes in one second.

For example, a person walking 3 meters per second is going faster than another person walking 2 meters per second.

mode

Unit 8 Lesson 2

The measure of central tendency for a one-variable data set that is the value(s) that occurs most often.

negative number

Unit 7 Lesson 1, Unit 7 Lesson 3, Unit 7 Lesson 4, Unit 7 Lesson 5

A negative number is a number that is less than zero. On a horizontal number line, negative numbers are usually shown to the left of 0.

A number line from -7 to 7 with some numbers not labeled. A red arrow extends from 0 to -7.

net

Unit 7 Lesson 2, Unit 7 Lesson 3, Unit 7 Lesson 4, Unit 7 Lesson 5

A net is a two-dimensional figure that can be folded to make a polyhedron.

Here is a net for a cube.

Six squares arranged with 4 in a row, 1 above the second square in the row, and one below the second square in the row.

opposite

Two numbers are opposites if they are the same distance from 0 and on different sides of the number line.

For example, 4 is the opposite of -4, and -4 is the opposite of 4. They are both the same distance from 0. One is negative, and the other is positive.

A number line from -5 to 5 with points at -4 and 4.

opposite vertex

Unit 1 Lesson 8

For each side of a triangle, there is one vertex that is not on that side. This is the opposite vertex.

For example, point $A$ is the opposite vertex to side $B C$ .

A triangle labeled A, B, and C at their vertexes.

origin

Unit 5 Lesson 7, Unit 5 Lesson 8, Unit 5 Lesson 9

The origin is the point $(0, 0)$ in the coordinate plane. This is where the horizontal axis and the vertical axis cross.

An x and y axis showing 0,0 also know as the origin.

outcome

Unit 1 Lesson 4, Unit 1 Lesson 5

An outcome of a chance experiment is one of the things that can happen when you do the experiment. For example, the possible outcomes of tossing a coin are heads and tails.

pace

Unit 2 Lesson 19

Pace is one way to describe how fast something is moving. Pace tells how much time it takes the object to travel a certain distance.

For example, Diego walks at a pace of 10 minutes per mile. Elena walks at a pace of 11 minutes per mile. Elena walks slower than Diego, because it takes her more time to travel the same distance.

parallelogram

A parallelogram is a type of quadrilateral that has two pairs of parallel sides.

Here are two examples of parallelograms.

A parallelogram with side lengths of 4.24 and 5 and angles of 45 degrees and 135. A second parallelogram with side of 9.34 and 4 with angles of 27.2 and 152.8 degrees.

per

Unit 2 Lesson 5, Unit 2 Lesson 6, Unit 2 Lesson 7

The word per means “for each.” For example, if the price is $5 per ticket, that means you will pay $5 for each ticket. Buying 4 tickets would cost $20, because $4 \cdot 5 = 20$ .

percent

Unit 2 Lesson 20, Unit 2 Lesson 22, Unit 2 Lesson 24

The word percent means “for each 100.” The symbol for percent is %.

For example, a quarter is worth 25 cents, and a dollar is worth 100 cents. We can say that a quarter is worth 25% of a dollar.

A diagram of two segments with different lengths. The top is labeled 1 Quarter and has a 25 cent segment. The bottom is labeled 1 dollar with a longer segment labeled 100 cents.

percent error

Unit 6 Lesson 10, Unit 6 Lesson 11

Percent error is a way to describe error, expressed as a percentage of the actual amount.

For example, a box is supposed to have 150 folders in it. Clare counts only 147 folders in the box. This is an error of 3 folders. The percent error is 2%, because 3 is 2% of 150. $3 \div 150 = 0.02$ .

percentage

Unit 2 Lesson 20, Unit 2 Lesson 21, Unit 2 Lesson 22, Unit 2 Lesson 24, Unit 6 Lesson 1, Unit 6 Lesson 2

A percentage is a rate per 100.

For example, a fish tank can hold 36 liters. Right now there is 27 liters of water in the tank. The percentage of the tank that is full is 75%.

A double number line with 5 evenly spaced tick marks. The top number line is labeled “volume, in liters” and starting with the first tick mark, 0, 9, 18, 27, and 36 are labeled. The bottom number line is not labeled and starting with the first tick mark 0, 25 percent, 50 percent, 75 percent, and 100 percent are labeled.

percentage decrease

Unit 6 Lesson 3, Unit 6 Lesson 4, Unit 6 Lesson 5, Unit 6 Lesson 6

A percentage decrease tells how much a quantity went down, expressed as a percentage of the starting amount.

For example, a store had $64$ hats in stock on Friday. The had $48$ hats left on Saturday. The amount went down by $16$ .

This was a $25 %$ decrease, because $16$ is $25 %$ of $64$ . $16 \div 64 = 0.25$

A two segment tape diagram labeled 100%. The white section is labeled 48 and 75% and the blue section is labeled 16 and 25%.

percentage increase

Unit 6 Lesson 3, Unit 6 Lesson 4, Unit 6 Lesson 5, Unit 6 Lesson 6

A percentage increase tell how much a quantity went up, expressed as a percentage of the starting amount.

For example, Elena had $$ 50$ in the bank on Monday. She had $$ 56$ on Tuesday. The amount went up by $$ 6$ .

This was a $12 %$ increase, because $6$ is $12 %$ of $50$ . $6 \div 50 = 0.12$

A two segment tape diagram labeled 112%. The white section is labeled 50 and 100% and the blue section is labeled 6 and 12%.

pi (π)

Unit 5 Lesson 12, Unit 5 Lesson 13

There is a proportional relationship between the diameter and circumference of any circle. The constant of proportionality is pi. The symbol for pi is $π$ .

We can represent this relationship with the equation $C = π d$ , where $C$ represents the circumference and $d$ represents the diameter.

Some approximations for $π$ are $\frac{22}{7}$ , 3.14, and 3.14159.

A graph of x axis labeled d and the y axis labeled C. Increments are 1 for both. There is a point labeled (1, pi).

polygon

Unit 1 Lesson 9

A polygon is a closed, two-dimensional shape with straight sides that do not cross each other.

Figure $A B C D E$ is an example of a polygon.

polyhedron

Unit 8 Lesson 8, Unit 8 Lesson 9, Unit 8 Lesson 10

A polyhedron is a closed, three-dimensional shape with flat sides. When we have more than one polyhedron, we call them polyhedra.

Here are some drawings of polyhedra.

population

A population is a set of people or things that we want to study.

For example, if we want to study the heights of people on different sports teams, the population would be all the people on the teams.

positive number

Unit 7 Lesson 1, Unit 7 Lesson 2, Unit 7 Lesson 4, Unit 7 Lesson 5

A positive number is a number that is greater than zero. On a horizontal number line, positive numbers are usually shown to the right of 0.

A number line from -7 to 7 with some numbers not labeled. A green arrow extends from 0 to 7.

prism

A prism is a type of polyhedron that has two bases that are identical copies of each other. The bases are connected by rectangles or parallelograms.

Here are some drawings of prisms.

A triangular prism, a pentagonal prism, and a rectangular prism.

probability

The probability of an event is a number that tells how likely it is to happen. A probability of 1 means the event will always happen. A probability of 0 means the event will never happen.

For example, the probability of selecting a moon block at random from this bag is $\frac{4}{5}$ .

A bag containing blocks. There are 4 blocks with moons on them and one block with a star.

product

The product of two numbers is the result of multiplying them together.

The product of 4 and 5 is $4 \cdot 5 = 20$ .

proportion

Unit 8 Lesson 12

A proportion of a data set is the fraction of the data in a given category.

For example, a class has 18 students. There are 2 left-handed students and 16 right-handed students in the class. The proportion of students who are left-handed is $\frac{2}{20}$ , or 0.1.

proportional relationship

Unit 5 Lesson 2

In a proportional relationship, the values for one quantity are each multiplied by the same number to get the values for the other quantity.

For example, in this table every value of $p$ is equal to 4 times the value of $s$ on the same row.

We can write this relationship as $p = 4 s$ . This equation shows that $p$ is proportional to $s$ .

$s$	$p$
2	8
3	12
5	20
10	40

pyramid

Unit 7 Lesson 11, Unit 7 Lesson 13

A pyramid is a type of polyhedron that has one base. All the other faces are triangles, and they all meet at a single vertex.

Here are some drawings of pyramids.

Three types of pyramids - rectangular, hexagonal, and heptagonal.

quadrant

The coordinate plane is divided into 4 regions called quadrants. The quadrants are numbered using Roman numerals, starting in the top right corner.

An xy-coordinate plane with the origin labeled "O". The region to the right of the y-axis and above the x-axis is labeled "Quadrant I." The region to the left of the y-axis and above the x-axis is labeled "Quadrant II." The region to the left of the y-axis and below the x-axis is labeled "Quadrant III." The region to the right of the y-axis and below the x-axis is labeled "Quadrant IV."

quadrilateral

Unit 1 Lesson 4, Unit 1 Lesson 9

A quadrilateral is a type of polygon that has 4 sides. A rectangle is an example of a quadrilateral. A pentagon is not a quadrilateral, because it has 5 sides.

quartile

Unit 8 Lesson 7

Quartiles are the numbers that divide a data set into four sections that each have the same number of values.

For example, in this data set the first quartile is 30. The second quartile is the same thing as the median, which is 43. The third quartile is 50.

$22$	$29$	$30$	$31$	$32$	$43$	$44$	$45$	$50$	$50$	$59$
		Q1			Q2			Q3

quotient

Unit 5 Lesson 11, Unit 5 Lesson 12, Unit 5 Lesson 13

The quotient of two numbers is the result of dividing the first by the second.

The quotient of 5 and 4 is $5 \div 4 = \frac{5}{4}$ .

radius

A radius is a line segment that goes from the center to the edge of a circle. A radius can go in any direction. Every radius of the circle is the same length. We also use the word radius to mean the length of this segment.

For example, $r$ is the radius of this circle with center $O$ .

A circle with a center O and line extending from the center to the edge labeled r.

random

Unit 2 Lesson 1, Unit 2 Lesson 2

Outcomes of a chance experiment are random if they are all equally likely to happen.

range

Unit 8 Lesson 7

The range is the distance between the smallest and largest values in a data set. For example, for the data set 3, 5, 6, 8, 11, 12, the range is 9, because $12 - 3 = 9$ .

ratio

A ratio is an association between two or more quantities.

For example, the ratio $3 : 2$ could describe a recipe that uses 3 cups of flour for every 2 eggs, or a boat that moves 3 meters every 2 seconds. One way to represent the ratio $3 : 2$ is with a diagram that has 3 blue squares for every 2 green squares.

A diagram showing 3 blue squares in a row and 2 green square below it. The picture is repeated.

rational number

Unit 6 Lesson 2, Unit 7 Lesson 1, Unit 7 Lesson 2, Unit 7 Lesson 18

A rational number is a fraction or the opposite of a fraction.

For example, 8 and -8 are rational numbers because they can be written as $\frac{8}{1}$ and $- \frac{8}{1}$ .

Also, 0.75 and -0.75 are rational numbers because they can be written as $\frac{75}{100}$ and $- \frac{75}{100}$ .

reciprocal

Unit 3 Lesson 7

Dividing 1 by a number gives the reciprocal of that number.

For example, the reciprocal of 12 is $\frac{1}{12}$ , and the reciprocal of $\frac{2}{5}$ is $\frac{5}{2}$ .

region

Unit 1 Lesson 1, Unit 1 Lesson 2, Unit 1 Lesson 3

A region is the space inside of a shape. Some examples of two-dimensional regions are inside a circle or inside a polygon. Some examples of three-dimensional regions are the inside of a cube or the inside of a sphere.

repeating decimal

Unit 6 Lesson 2

A repeating decimal has digits that keep going in the same pattern over and over. The repeating digits are marked with a line above them.

For example, the decimal representation for $\frac{1}{3}$ is $0. \overset{―}{3}$ , which means 0.3333333 … The decimal representation for $\frac{25}{22}$ is $1.1 \overset{―}{36}$ which means 1.136363636 …

representative

Unit 8 Lesson 9, Unit 8 Lesson 10

A sample is representative of a population if its distribution resembles the population’s distribution in center, shape, and spread.

For example, this dot plot represents a population.

A dot plot of dollars per pound of catfish spread between 1.6 and 2.8. There is data spread through the plot with the most dots at 1.8

This dot plot shows a sample that is representative of the population.

A dot plot of dollars per pound of catfish spread between 1.6 and 2.8. There is data spread through the plot, but less data overall than prior plot.

same rate

Unit 2 Lesson 7

We use the words same rate to describe two situations that have equivalent ratios.

For example, a sink is filling with water at a rate of 2 gallons per minute. If a tub is also filling with water at a rate of 2 gallons per minute, then the sink and the tub are filling at the same rate.

sample

Unit 8 Lesson 8, Unit 8 Lesson 9, Unit 8 Lesson 10

A sample is part of a population. For example, a population could be all the seventh grade students at one school. One sample of that population is all the seventh grade students who are in band.

sample space

Unit 7 Lesson 3, Unit 7 Lesson 4, Unit 7 Lesson 5

The sample space is the list of every possible outcome for a chance experiment.

For example, the sample space for tossing two coins is:

heads-heads	tails-heads
heads-tails	tails-tails

A picture of the face of a Sacagawea dollar coin.

sign

The sign of any number other than 0 is either positive or negative.

For example, the sign of 6 is positive. The sign of -6 is negative. Zero does not have a sign, because it is not positive or negative.

solution to an equation

Unit 4 Lesson 2, Unit 4 Lesson 3, Unit 4 Lesson 4, Unit 4 Lesson 5, Unit 7 Lesson 16, Unit 7 Lesson 17

A solution to an equation is a number that can be used in place of the variable to make the equation true.

For example, 7 is the solution to the equation $m + 1 = 8$ , because it is true that $7 + 1 = 8$ . The solution to $m + 1 = 8$ is not 9, because $9 + 1 \neq 8$ .

speed

Unit 2 Lesson 19

Speed is one way to describe how fast something is moving. Speed tells how much distance the object travels in a certain amount of time.

For example, Tyler walks at a speed of 4 miles per hour. Priya walks at a speed of 5 miles per hour. Priya walks faster than Tyler, because she travels more distance in the same amount of time.

spread

Unit 8 Lesson 2, Unit 8 Lesson 3

The spread of a set of numerical data tells how far apart the values are.

For example, the dot plots show that the travel times for students in South Africa are more spread out than for New Zealand.

A dot plot for New Zealand and one for South Africa. The data for New Zealand ranges from about 3 to 24, while South Africa is from 5 to 60.

squared

Unit 4 Lesson 11, Unit 4 Lesson 12, Unit 5 Lesson 15, Unit 5 Lesson 16

We use the word squared to mean “to the second power.” This is because a square with side length $s$ has an area of $s \cdot s$ , or $s^{2}$ .

sum