## Math Expressions Common Core Grade 1 Unit 3 Lesson 3 Answer Key Solve Equations with Unknown Partners

**Math Expressions Grade 1 Unit 3 Lesson 3 Homework**

**Count on to find the unknown partner.**

Question 1.

3 + __ = 7

Answer:

3 + 4 = 7

Explanation:

unknown partner number is 4.

Since adding 4 to 3 is 7.

So answer is 4.

So 3 + 4 = 7

Question 2.

5 + __ = 10

Answer:

5 + 5 = 10

Explanation:

unknown partner number is 5.

Since adding 5 to 5 is 10.

So answer is 5.

So 5 + 5 = 10

Question 3.

2 + __ = 6

Answer:

2 + 4 = 6

Explanation:

unknown partner number is 4.

Since adding 2 to 4 is 6.

So answer is 4.

So 2 + 4 = 6

Question 4.

4 + __ = 8

Answer:

4 + 4 = 8

Explanation:

unknown partner number is 4.

Since adding 4 to 4 is 8.

So answer is 4.

So 4 + 4 = 8

Question 5.

7 + __ = 9

Answer:

7 + 2 = 9

Explanation:

unknown partner number is 2.

Since adding 2 to 7 is 9.

So answer is 2.

So 7 + 2= 9

Question 6.

5 + __ = 9

Answer:

5 + 4 = 9

Explanation:

unknown partner number is 4.

Since adding 4 to 5 is 9.

So answer is 4.

So 5 + 4 = 9

Question 7.

6 + __ = 9

Answer:

6 + 3 = 9

Explanation:

unknown partner number is 3.

Since adding 6 to 3 is 9.

So answer is 3.

So 6 + 3 = 9

Question 8.

4 + __ = 10

Answer:

4 + 6 = 10

Explanation:

unknown partner number is 6.

Since adding 6 to 4 is 10.

So answer is 6.

So 4 + 6 = 10

Question 9.

4 + __ = 7

Answer:

4 + 3 = 7

Explanation:

unknown partner number is 3.

Since adding 3 to 4 is 7.

So answer is 3.

So 4 + 3 = 7

**Count on to find the number of animals in the barn.**

Question 10.

8 total

Answer:

Explanation:

There are 8 hens

in that 3 are out side

so, 5 in the barn

Question 11.

9 total

Answer:

Explanation:

There are 9 sheep

5 are outside

4 in the barn

Question 12.

10 total

Answer:

Explanation:

There are 10 cows

4 are outside

6 are in barn

Question 13.

7 total

Answer:

Explanation:

there are 7 horses

2 are outside

5 in the barn

**Math Expressions Grade 1 Unit 3 Lesson 3 Remembering**

**Write the partners and the switched partners.**

Question 1.

Count on. Write the total.

Answer:

Explanation:

Written the 7 partners

and the switched partners.

Question 2.

Answer:

Explanation:

7 as group and counted from that 3 strawberries

7 + 3 = 10

Question 3.

Answer:

Explanation:

5 as group and counted from that 7 apples

5 + 2 = 7

Question 4.

Answer:

Explanation:

2 as group and counted from that 4 oranges

2 + 4 = 6

Question 5.

Answer:

Explanation:

8 as group and counted from that 1 pumpkin

8 + 1 = 9

**Solve the story problem. Show your work. Use drawings, numbers, or words.**

Question 6.

Ben sees 9 ducks ¡n the pond. 3 are white. The others are black. How many ducks are black?

Answer:

Explanation:

Ben sees 9 ducks ¡n the pond.

3 are white.

The others are black.

6 ducks are black

Question 7.

**Stretch Your Thinking** Write three addition equations with a total of 10.

Answer:

5 + 5 = 10

7 + 3 = 10

6 + 4 = 10

Explanation:

written the 3 addition equations