Section A: Practice Problems Add and Subtract Within 20

Problem 1 (Pre-Unit)

The picture shows how Jada sorted the shapes on her table.

Data Chart. Shapes on the Table. Circles, 5. Squares, 8. Triangles, 6.

Use the picture to answer the questions:

How many squares were on the table?
How many triangles were on the table?
Which shape has the smallest number?

Problem 2 (Pre-Unit)

The table shows the favorite magical powers of some students.

Data Chart. Favorite Magical Power. Read minds, 6. Become Invisible, 8. Fly, 3.

How many more students prefer being invisible to flying?
How many fewer students prefer flying to reading minds?

Problem 3 (Pre-Unit)

Here are some shapes:

Collection of shapes: circles, triangles, rectangles.

Fill out the chart showing how many of each shape there are.

circles	triangles	rectangles

Problem 4 (Lesson 1)

Find the value of each expression.

$9 - 2$
$5 + 3$
$2 + 8$
$7 - 4$
$10 - 3$
$1 + 6$

Problem 5 (Lesson 2)

Jada is playing “What’s Behind my Back?” with Han. Han has 10 cubes and shows Jada these connecting cubes.

How many connecting cubes are behind Han’s back?
What’s an addition equation that you can write that matches the game?
What’s a subtraction equation that you can write that matches the game?

Problem 6 (Lesson 3)

Find the number that makes each equation true. Show your thinking using drawings, numbers, or words.

$20 - 10 =$
$17 +$ $= 20$
$20 = 5 +$
$7 = 20 -$

Problem 7 (Lesson 4)

Here are the numbers on seven cards:

Choose three of the numbers to add to get as close as you can to 20.
Write an equation to show your choice.

Problem 8 (Lesson 5)

Find the value of each sum. Show your thinking using drawings, words, or numbers.

$31 + 15$
$17 + 8$
$26 + 17$

Problem 9 (Exploration)

Choose 3 of these 7 cards and get as close to 20 as possible.

Can you make 20?
Can you make 20 in more than 1 way?
Can you make 20 using the 1?

Problem 10 (Exploration)

Clare has a set of cards numbered 1, 2, 3, 4, 5, 6, 7, 8, 9.
She picks out seven of the cards. Clare was NOT able to make 20 with 3 of her 7 cards. Which cards do you think she picked out if she was NOT able to make 20?