All the solutions provided in McGraw Hill My Math Grade 1 Answer Key PDF Chapter 6 Lesson 8 Relate Addition and Subtraction of Tens will give you a clear idea of the concepts.
McGraw-Hill My Math Grade 1 Answer Key Chapter 6 Lesson 8 Relate Addition and Subtraction of Tens
Explore and Explain
Teacher Directions: Use 
to model. There are 50 people ice skating. 30 more people join them. How many people are ice skating in oil? Write the number. Write a related subtraction problem Explain how the number sentences are related.
Answer:
Explanation:
There are 50 people ice skating
30 more people join them
5 tens + 3 tens = 8 tens
50 + 30 = 80
So, 80 people are ice skating
80 – 50 = 30 is the related subtraction sentence.
See and Show
Find 70 – 20.
To find 70 – 20, think 20 + 
= 70.
So, 70 – 20 = .
Helpful Hint
20 + 50 = 70,
so 70 – 20 = 50.
Use related facts to add and subtract.
Question 1.
10 + _______________ = 30
30 – 10 = ______________
Answer:
20
Explanation:
10 + 20 = 30
The related subtraction equation is 30 – 10 = 20.
Question 2.
30 + _______________ = 60
60 – 30 = _______________
Answer:
30
Explanation:
30 + 30 = 60
The related subtraction equation is 60 – 30 = 30.
Question 3.
40 + _______________ = 50
50 – 40 = _______________
Answer:
10
Explanation:
40 + 10 = 50
The related subtraction equation is 50 – 40 = 10.
Question 4.
20 + _______________ = 40
40 – 20 = _______________
Answer:
20
Explanation:
20 + 20 = 40
The related subtraction equation is 40 – 20 = 20.
Subtract. Write a related addition fact.
Question 5.
80 – 50 = _______________
_______________ + _______________ = _______________
Answer:
80 – 50 = 30
Explanation:
80 – 50 = 30
The related addition fact is 50 + 30 = 80.
Question 6.
90 – 70 = _______________
_______________ + _______________ = _______________
Answer:
90 – 70 = 20
Explanation:
90 – 70 = 20
The related addition fact is 70 + 20 = 90.
Talk Math Tell the related addition fact you would use to find 60 – 40. Explain.
Answer:
60 – 40 = 20
The related addition fact that i use to solve 60 – 40 is 20 + 40 = 60.
On My Own
Use related facts to add and subtract.
Question 7.
50 + _______________ = 70
70 – 50 = _______________
Answer:
20
Explanation:
50 + 20 = 70
The related subtraction equation is 70 – 50 = 20.
Question 8.
20 + _______________ = 80
80 – 20 = _______________
Answer:
60
Explanation:
20 + 60 = 80
The related subtraction equation is 80 – 20 = 60.
Question 9.
40 + _______________ = 90
90 – 40 = _______________
Answer:
50
Explanation:
40 + 50 = 90
The related subtraction equation is 90 – 40 = 50.
Question 10.
50 + _______________ = 60
60 – 50 = _______________
Answer:
10
Explanation:
50 + 10 = 60
The related subtraction equation is 60 – 50 = 10.
Question 11.
20 + _______________ = 50
50 – 20 = _______________
Answer:
30
Explanation:
20 + 30 = 50
The related subtraction equation is 50 – 20 = 30.
Question 12.
30 + _______________ = 70
70 – 30 = _______________
Answer:
40
Explanation:
30 + 40 = 70
The related subtraction equation is 70 – 30 = 40.
Subtract. Write a related addition fact.
Question 13.
40 – 10 = _______________
_______________ + _______________ = _______________
Answer:
40 – 10 = 30
Explanation:
40 – 10 = 30
The related addition fact is 10 + 30 = 40.
Question 14.
90 – 10 = _______________
_______________ + _______________ = _______________
Answer:
90 – 10 = 80
Explanation:
90 – 10 = 80
The related addition fact is 80 + 10 = 90.
Question 15.
30 – 20 = _______________
_______________ + _______________ = _______________
Answer:
30 – 20 = 10
Explanation:
30 – 20 = 10
The related addition fact is 10 + 20 = 30.
Question 16.
90 – 50 = _______________
_______________ + _______________ = _______________
Answer:
90 – 50 = 40
Explanation:
90 – 50 = 40
The related addition fact is 50 + 40 = 90.
Problem Solving
Use 
to subtract. Write a related addition fact.
Question 17.
A toy store has 60 video games. 40 of them get sold. How many video games does the store have left?
_______________ – _______________ = _______________
_______________ + _______________ = _______________
Answer:
Explanation:
A toy store has 60 video games
40 of them get sold
60 – 40 = 20
So, the store have 20 video games left
The related addition fact is 40 + 20 = 60.
Question 18.
Marcus has 90 basketball cards. He gives 20 cards to his brother. How many cards does Marcus have left?
_______________ – _______________ = _______________
_______________ + _______________ = _______________
Answer:
Explanation:
Marcus has 90 basketball cards
He gives 20 cards to his brother
90 – 20 = 70
So, Marcus have 70 cards left
The related addition fact is 70 + 20 = 90.
Write Math Write a word problem using the number sentence 20 + 30 = 50 or 50 – 20 = 30.
Answer:
There are 50 children in the park. 30 among them are girls. How many boys are in the park?
McGraw Hill My Math Grade 1 Chapter 6 Lesson 8 My Homework Answer Key
Practice
Use related facts to add and subtract.
Question 1.
10 + _______________ = 20
20 – 10 = _______________
Answer:
10
Explanation:
10 + 10 = 20
The related subtraction equation is 20 – 10 = 10.
Question 2.
40 + _______________ = 60
60 – 40 = _______________
Answer:
20
Explanation:
40 + 20 = 60
The related subtraction equation is 60 – 40 = 20.
Question 3.
50 + _______________ = 90
90 – 50 = _______________
Answer:
40
Explanation:
50 + 40= 90
The related subtraction equation is 90 – 50 = 40.
Question 4.
20 + _______________ = 30
30 – 20 = _______________
Answer:
10
Explanation:
20 + 10 = 30
The related subtraction equation is 30 – 20 = 10.
Question 5.
30 + _______________ = 80
80 – 30 = _______________
Answer:
50
Explanation:
30 + 50 = 80
The related subtraction equation is 80 – 30 = 50.
Question 6.
10 + _______________ = 50
50 – 10 = _______________
Answer:
40
Explanation:
10 + 40 = 50
The related subtraction equation is 50 – 10 = 40.
Subtract. Write a related addition fact.
Question 7.
70 – 60 = _______________
_______________ + _______________ = _______________
Answer:
70 – 60 = 10
Explanation:
70 – 60 = 10
The related addition fact is 10 + 60 = 70.
Question 8.
40 – 20 = _______________
_______________ + _______________ = _______________
Answer:
40 – 20 = 20
Explanation:
40 – 20 = 20
The related addition fact is 20 + 20 = 40.
Write the subtraction number sentence. Then write a related addition fact.
Question 9.
Ming’s team scores 50 points in their first basketball game and 30 points in their second game. How many more points did they score in their first game?
_______________ – _______________ = _______________
_______________ + _______________ = _______________
Answer:
50 – 30 = 20
30 + 20 = 50
Explanation:
Ming’s team scores 50 points in their first basketball game
30 points in their second game
50 – 30 = 20 is the subtraction number sentence that solves the problem
They scored 20 points in the first game
The related addition fact is 30 + 20 = 50.
Test Practice
Mark the related subtraction fact.
Question 10.
40 + _______________ = 60
(A) 40 + 10 = 60
(B) 60 + 30 = 90
(C) 60 – 40 = 20
(D) 60 – 40 = 10
Answer:
(C) 60 – 40 = 20
Explanation:
40 + 20 = 60
So, the related subtraction fact is 60 – 40 = 20.
Math at Home Have your child solve the following subtraction fact: 80 – 60 = ____________. Ask them to say the related addition fact that can help them solve the problem.
Answer:
80 – 60 = 20
Explanation:
80 – 60 = 20
The related addition fact is 60 + 20 = 80.