Adding/Subtracting by 10s

Front

What is 80 + 10?

Back

90

Front

What is 20 + 30?

Back

50

Front

What is 55 - 10?

Back

45

Front

What is 90 - 10?

Back

80

Front

What is 76 - 20?

Back

56

Front

What does it mean to add by 10s?

Back

Adding by 10s means increasing a number by 10, like going from 20 to 30.

Front

What does it mean to subtract by 10s?

Back

Subtracting by 10s means decreasing a number by 10, like going from 30 to 20.

Front

If you have 30 and you add 10, what do you get?

Back

40

Front

If you have 50 and you subtract 10, what do you get?

Back

40

Front

What is 100 - 10?

Back

90