# Eureka Math Grade 1 Module 1 Lesson 21 Answer Key

## Engage NY Eureka Math 1st Grade Module 1 Lesson 21 Answer Key

### Eureka Math Grade 1 Module 1 Lesson 21 Problem Set Answer Key

Add the numbers on the pairs of cards. Write the number sentences. Color doubles red. Color doubles plus 1 blue.

Question 1. Answer: 6
The above equation shows a pair of cards
ADD the pair of cards
By adding 3 and 3
we get 6 Question 2. Answer:8
The above equation shows a pair of cards
ADD the pair of cards
By adding 4 wth 4
we get 8 Question 3. Answer:7
The above equation shows a pair of cards
ADD the pair of cards
By adding 3 wth 4
we get 7 Question 4. Answer:9
The above equation shows a pair of cards
ADD the pair of cards
By adding 5 wth 4
we get 9 Solve. Use your doubles to help. Draw and write the double that helped.

Question 5. Answer: 9
Given the numbers are 5 and 4
To find the missing number
Add 5 with 4
we get 9 Question 6. Answer:7
Given the numbers are 3 and 4
To find the missing number
Add 3 with 4
we get 7 Question 7.
Solve the doubles and the doubles plus 1 number sentences. Answer: Question 8.
Show how this strategy can help you solve 5 + 6 = Answer:11
Given the numbers are 5 and 6
To find the missing number
Add 5 with 6
we get 11 Question 9.
Write a set of 4 related addition facts for the number sentences of Problem 7(d).
Answer: 4+4 =8
8+4+4
4+5=9
9=4+5

### Eureka Math Grade 1 Module 1 Lesson 21 Exit Ticket Answer Key

Write the double and double plus 1 number sentence for each 5-group card. Answer: ### Eureka Math Grade 1 Module 1 Lesson 21 Homework Answer Key

Question 1.
Draw the 5-group card to show a double. Write the number sentence to match the cards.
a. Answer:The double  fact that hlped to solve the euqation is
4+4=8
For which the double+1 fact is 4+5=9 b. Answer:The double  fact that hlped to solve the euqation is
3+3=6
For which the double+1 fact is 3+4=7 c. Answer:The double  fact that hlped to solve the euqation is
5+5=10
For which the double+1 fact is 5+6=11 Question 2.
Fill in the 5-group cards in order from least to greatest, double the number, and write the number sentences.
a. b. c. d. e. Answer: Question 3.
Solve the number sentences.
a. 3 + 3 = __

Answer:6
Given : two numbers are 3 and 3
By adding 3 with 3 we get 6
3 + 3 = 6

b. 5 + __ = 10

Answer:10
Given : two numbers are 5 and 10
by subracting 5 from 10 we get 5
10-5=5
so the issing number is 5
5 + 5 = 10

c. 1 + __ = 2

Answer: 1
Given : two numbers are 1 and 2
by subracting 1 from 2 we get 1
2-1=1
so the issing number is 1
1+1=2

d. 4 = __ + 2

Answer:2
Given : two numbers are 4 and 2
by subracting 2 from 4 we get 2
4-2=2
so the issing number is 2
4 = 2 + 2

e. 8 = 4 + __

Answer:4
Given : two numbers are 4 and 8
by subracting 4 from 8 we get4
8-4=4
so the issing number is 5
8 = 4 + 4

Question 4.
Match the top cards to the bottom cards to show doubles plus 1.
a. b. c. d. Answer: Question 5.
Solve the number sentences. Write the double fact that helped you solve the double plus 1.
a. Answer: The double +1 fact that hlped to solve the euqation is
2+3=5
For which the double fact is 2+2=4 b. Answer:The double +1 fact that hlped to solve the euqation is
3+4=7
For which the double fact is 3+3=6 c. Answer:The double +1 fact that hlped to solve the euqation is
4+5=9
For which the double fact is 4+4=8 Scroll to Top