All the solutions provided in McGraw Hill My Math Grade 1 Answer Key PDF Chapter 6 Lesson 7 Count Back by 10s will give you a clear idea of the concepts.
McGraw-Hill My Math Grade 1 Answer Key Chapter 6 Lesson 7 Count Back by 10s
Explore and Explain
70 – 30 = ______________
Teacher Directions: Use 
to model. Samuel starts at 70. He hops and lands on 70 – 30. Draw a circle around the number where he lands. Write the number. Explain to a classmate how you found the answer.
Answer:
Explanation:
I used to model the problem
Samuel starts at 70
He hops and lands on 70 – 30
I drew a circle around the number 40
I counted back and jumped
70 – 30 = 40.
See and Show
Use a number line to subtract numbers by tens.
Helpful Hint
Start at 50. Count back by tens to find the difference. 40, 30, 20, 10.
Use the number line to help you subtract. Write the difference.
Question 1.
80 – 30 = ______________
Answer:
Explanation:
Use a number line to subtract numbers by tens
Start at 80
Count back by tens to find the difference 70, 60, 50
So, 80 – 30 = 50.
Question 2.
50 – 20 = _______________
Answer:
Explanation:
Use a number line to subtract numbers by tens
Start at 50
Count back by tens to find the difference 40, 30
So, 50 – 20 = 30.
Talk Math Explain how you can use a number line to help you subtract by tens.
Answer:
I can use number line and count backward by jumping backwards by 10
In this way i can subtract by 10’s.
McGraw Hill My Math Grade 1 Chapter 6 Lesson 7 My Homework Answer Key
Practice
Use the number line to help you subtract. Write the difference.
Question 1.
60 – 20 = _______________
Answer:
Explanation:
Use a number line to subtract numbers by tens
Start at 60
Count back by tens to find the difference 50, 40
So, 60 – 20 = 40.
Question 2.
90 – 10 = _________________
Answer:
Explanation:
Use a number line to subtract numbers by tens
Start at 90
Count back by tens to find the difference 80
So, 90 – 10 = 80.
Question 3.
80 – 30 = ________________
Answer:
Explanation:
Use a number line to subtract numbers by tens
Start at 80
Count back by tens to find the difference 70, 60, 50
So, 80 – 30 = 50.
Question 4.
50 – 40 = _______________
Answer:
Explanation:
Use a number line to subtract numbers by tens
Start at 50
Count back by tens to find the difference 40, 30, 0, 10
So, 50 – 40 = 10.
Question 5.
80 – 10 = _______________
Answer:
Explanation:
Use a number line to subtract numbers by tens
Start at 80
Count back by tens to find the difference 70
So, 80 -10 = 70.
Question 6.
30 – 10 = _______________
Answer:
Explanation:
Use a number line to subtract numbers by tens
Start at 30
Count back by tens to find the difference 20
So, 30 -10 = 20.
Question 7.
70 – 20 = _______________
Answer:
Explanation:
Use a number line to subtract numbers by tens
Start at 70
Count back by tens to find the difference 60, 50
So, 70 -20 = 50.
Question 8.
Answer:
Explanation:
The difference of 90 and 30 is 60
90 – 30 = 60.
Question 9.
Answer:
Explanation:
The difference of 40 and 10 is 30
40 – 10 = 30.
Question 10.
Answer:
Explanation:
The difference of 60 and 40 is 20
60 – 40 = 20.
Question 11.
There are 30 children in line to go down a slide. 10 children go down the slide. How many children are still in line?
_____________ children
Answer:
Explanation:
There are 30 children in line to go down a slide
10 children go down the slide
Use a number line to subtract numbers by tens
Start at 30
Count back by tens to find the difference 20
So, 30 – 20 = 10
Therefore, 10 children are still in the line.
Test Practice
Question 12.
70 – 10 = _________________
(A) 60
(B) 70
(C) 80
(D) 90
Answer:
(A) 60
Explanation:
Start at 70
Count back by tens to find the difference 60
So, 70 – 10 = 60.
Math at Home Have your child show 60 – 20 using a number line. Have him or her explain how they use the number line as they subtract.
Answer:
Explanation:
Use a number line to subtract numbers by tens
Start at 60
Count back by tens to find the difference 50, 40
So, 60 – 20 = 40.