Refer to our Texas Go Math Grade 1 Answer Key Pdf to score good marks in the exams. Test yourself by practicing the problems from Texas Go Math Grade 1 Lesson 13.4 Answer Key Unknown Numbers.

## Texas Go Math Grade 1 Lesson 13.4 Answer Key Unknown Numbers

**Explore**

Listen to the problem. Use to show the story. Draw to show your work.

Answer:

FOR THE TEACHER • Read the problem. Calvin has 7 toy cars that are red. He has some blue toy cars. He has 10 toy cars. How many blue toy cars does Calvin have?

Answer:

Calvin has red toy cars = 7

Total number of toy cars are 10

He has some blue cars.

Total number of blue cars = 10 – 7 = 3

**Math Talk**

**Mathematical Processes**

How many toy cars are blue? Explain how you got your answer.

Answer:

**Model and Draw**

What are the unknown numbers?

Use what you know about related facts to find the unknown parts.

Answer:

The unknown parts is 3.

**Share and Show**

Use to find the unknown numbers. Write the numbers.

Question 1.

8 + __________ = 15

15 – 8 = __________

Answer:

8 + 7 = 15

15 – 8 = 7

Question 2.

13 = 9 + __________

__________ = 13 – 9

Answer:

13 = 9 + 4

4 = 13 – 9

Question 3.

5 + __________ = 14

14 – 5 = __________

Answer:

5 + 9 = 14

14 – 5 = 9

Question 4.

14 = 6 + __________

__________ = 14 – 6

Answer:

14 = 6 + 8

8 = 14 – 6

Question 5.

9 + __________ = 16

16 – 9 = __________

Answer:

9 + 7 = 16

16 – 9 = 7

Question 6.

17 = 8 + __________

__________ = 17 – 8

Answer:

17 = 8 + 9

9 = 17 – 8

**Problem Solving**

Write the unknown numbers. Use if you need to.

Question 7.

7 + __________ = 15

15 – 7 = __________

Answer:

7 + 8 = 15

15 – 7 = 8

Question 8.

5 + __________ = 11

11 – 5 = __________

Answer:

5 + 6 = 11

11 – 5 = 6

Question 9.

__________ + 10 = 20

20 – 10 = __________

Answer:

10 + 10 = 20

20 – 10 = 10

Question 10

__________ + 9 = 16

16 – 9 = __________

Answer:

7 + 9 = 16

16 – 9 = 7

Question 11.

**H.O.T. Solve.** Rick has 10 party hats. He needs l hats for his party. How many more party hats does Rick need?

_________ party hats

Answer:

Question 12.

**H.O.T. Multi-Step** Solve. Use if you need to.

There were 15 children at the park. Some children went home. Then 4 more children came to the park. Now there are 13 children at the park. How many children went home?

__________ children

Answer:

Total number of children at the park = 15

More children came to park = 4

Total number of children came to park = 19

Now children at the park = 13

Children went to home = 19 – 13 = 6

**Daily Assessment Task**

Use . Choose the correct answer.

Question 13.

Analyze 14 cars are at the starting line. 10 cars cross the finish line. How many cars did not cross the finish line?

10 + ________ = 14

(A) 4

(B) 9

(C) 5

Answer:

Cars at the starting line = 14.

Cars cross the finish line = 10

The cars did not cross the line are 14 – 10 = 4

Option A is the correct answer.

Question 14.

Nick has 3 blue cubes in his hand. The cubes on his desk are yellow. He has 12 cubes. How many yellow cubes does Nick have?

3 + _________ = 12

12 – __________ = 3

(A) 6

(B) 9

(C) 4

Answer:

Total number of cubes near Nick = 12

Nick has blue cubes in his hand = 3

The remaining cubes are yellow colour

Total number of yellow colour cubes = 12 – 3 = 9.

Option B is the correct answer.

Question 15.

**Multi-Step** Tori counts the toys in her toy box. She has 3 bears and 3 cars. The rest are dolls. She has 12 toys in her toy box. How many dolls does Tori have?

(A) 9

(B) 5

(C) 6

Answer:

Tori has 3 bears and 3 cars.

Total number of toys in the toy box are 12

The rest of the toys are 12 – 3 + 3 = 6.

Option C is the correct answer.

Question 16.

**Texas Test Prep** What is the unknown number?

9 + _________ = 18

(A) 8

(B) 9

(C) 11

Answer:

9 is the unknown number.

**TAKE HOME ACTIVITY** • Hove your child exploin how using subtraction can help him or her find the unknown number in 7 + _________ = 16.

Answer:

7 + 9 = 16

### Texas Go Math Grade 1 Lesson 13.4 Homework and Practice Answer Key

**Write the unknown numbers. Draw if you need to.**

Question 1.

9 + _________ = 18

18 – 9 = _________

Answer:

9 + 9 = 18

18 – 9 = 9

Question 2.

7 + _________ = 15

15 – 7 = _________

Answer:

7 + 8 = 15

15 – 7 = 8

Question 3.

12 = 8 + _________

_________ = 12 – 8

Answer:

12 = 8 + 7

7 = 12 – 7

Question 4.

_________ + 6 = 15

15 – 6 = _________

Answer:

9 + 6 = 15

15 – 6 = 9

**Problem Solving**

Question 5.

Mr. Brown has 7 sleeping bags. He has 16 campers. How many more sleeping bags does Mr. Brown need?

___________ sleeping bags

Answer:

Mr. Brown has sleeping bags = 7

He has campers = 16

More sleeping bags does Mr. Brown need = 16 – 7 = 9

**Lesson Check**

**Choose the correct answer.**

Question 6.

14 children are walking to raise money. 8 children finish the walk. How many children did not finish the walk?

8 + ________ = 14

(A) 4

(B) 7

(C) 6

Answer:

Children are walking to raise money = 14

Children finish the walk = 8

Children did not finish the walk = 14 – 8 = 6

Question 7.

Jasmine has 6 red pencils in her pencil case. The pencils in her hand are blue. She has 13 pencils. How many blue pencils does Jasmine have?

6 + __________ = 13

13 – _________ = 6

(A) 6

(B) 1

(C) 7

Answer:

Total number of pencils = 13

Jasmine has red pencils in her pencil case = 6

Pencils in her hand are blue.

Number of blue pencils = 13 – 6 = 7

Number of blue pencils are 7.

Question 8.

What is the unknown number?

________ + 8 = 16

(A) 8

(B) 9

(C) 7

Answer:

8 is the unknown number.

Question 9.

**Multi-step** Sam has 17 shirts in his drawer. He has 5 red shirts and 4 green shirts. The rest of his shirts are blue. How many blue shirts does Sam have?

(A) 9

(B) 8

(C) 10

Answer:

Total number of Sam has shirts in his drawer = 17

Total number of red shirts = 5

Total number of green shirts = 4

The remaining shirts are blue

Number of blue shirts = 17 – 5 + 4 = 8

Total number of blue shirts are 8.