Lesson 3: Practice Problems

Problem 1

Here is a base-ten diagram that represents 1.13. Use the diagram to find $1.13 - 0.46$ .

Explain or show your reasoning.

Problem 2

Compute the following sums. If you get stuck, consider drawing base-ten diagrams.

$0.027 + 0.004$
$0.203 + 0.1$
$1.2 + 0.145$

Problem 3

A student said we cannot subtract 1.97 from 20 because 1.97 has two decimal digits and 20 has none. Do you agree with his statement? Explain or show your reasoning.

Problem 4

Decide which calculation shows the correct way to find $0.3 - 0.006$ and explain your reasoning.

Problem 5

Complete the calculations so that each shows the correct difference.

Problem 6 From Unit 5 Lesson 1

The school store sells pencils for $0.30 each, hats for $14.50 each, and binders for $3.20 each. Elena would like to buy 3 pencils, a hat, and 2 binders. She estimated that the cost will be less than $20.

Do you agree with her estimate? Explain your reasoning.
Estimate the number of pencils could she buy with $5. Explain or show your reasoning.

Problem 7 From Unit 4 Lesson 15

A rectangular prism measures $7 \frac{1}{2}$ cm by 12 cm by $15 \frac{1}{2}$ cm.

Calculate the number of cubes with edge length $\frac{1}{2}$ cm that fit in this prism.
What is the volume of the prism in ${cm}^{3}$ ? Show your reasoning. If you are stuck, think about how many cubes with $\frac{1}{2}$ -cm edge lengths fit into $1 {cm}^{3}$ .

Problem 8 From Unit 2 Lesson 12

At a constant speed, a car travels 75 miles in 60 minutes. How far does the car travel in 18 minutes? If you get stuck, consider using the table.

minutes	distance in miles
$60$	$75$
$6$
$18$