Counting Back with Tens
Use a number line to help you subtract 60-20.
40
tens ones
5 2
+ 7
59
What is a difference?
The answer to a subtraction problem.
Make a fact family using 10, 20, 30
10 + 20 = 30
20 + 10 = 30
30 - 20 = 10
30 - 10 = 20
1 ten + 4 tens = _____ tens
10 + 40 = _____
5 tens
50
Use a number line to help you subtract 80-50.
30
tens ones
3 3
+ 5
38
In the number 72, the 7 is in the ones/tens place.
Tens
Make a fact family using 20, 40, 60
20 + 40 = 60
40 + 20 = 60
60 - 20 = 40
60 - 40 = 20
3 tens + 4 tens = _____ tens
30 + 40 = _____
7 tens
70
Joey has 50 stamps in his collection. He lets Sam borrow 20 of them. How many stamps does Joey have left?
30 stamps
tens ones
4 8
+ 2
50
In the number 85, the 5 is in the ones/tens place.
ones
Make a fact family using 70, 30, 100
70 + 30 = 100
30 + 70 = 100
100 - 70 = 30
100 - 30 = 70
88 + 10 = _____
98
Melinda has 80 buttons. She uses 30 of them to make a shirt. How many buttons does she have left?
50 buttons
tens ones
2 1
+ 8
29
What is a sum?
The answer to an addition problem.
How does knowing 4+3 help you know 40+30? What is 40+30?
*Students will answer in their own words
40+30=70
42 + 30 = _____
72
Jessica and Taylor have 90 stickers. They give Jamie 60 of them. How many stickers do Jessica and Taylor have left?
30 stickers
tens ones
5 5
+ 4
59
Use your own words to explain the difference between adding and subtracting.
Adding is putting numbers together. Subtracting is taking away.
Make a fact family using 65, 35, 100
65 + 35 = 100
35 + 65 = 100
100 - 35 = 65
100 - 65 = 35
33 + 12 = _____
45