WHAT IS MENTAL MATH WITHIN 100?
Mental math is math that you do without using a pencil and paper. Friendly numbers and skip counting can help you add and subtract using mental math.
To better understand mental math within 100…
WHAT IS MENTAL MATH WITHIN 100?.
Mental math is math that you do without using a pencil and paper. Friendly numbers and skip counting can help you add and subtract using mental math.
To better understand mental math within 100…
LET’S BREAK IT DOWN!
What are friendly numbers?
Friendly numbers are numbers that are easy to add. It is easy to add 10 and another number. 10 + 2 = 12. It is easy to add together numbers that make a ten. 4 + 6 = 10. Doubles are also easier to add. 6 + 6 = 12.
What are friendly numbers? Friendly numbers are numbers that are easy to add. It is easy to add 10 and another number. 10 + 2 = 12. It is easy to add together numbers that make a ten. 4 + 6 = 10. Doubles are also easier to add. 6 + 6 = 12.
Find how many crayons in all.
You have 11 crayons. A friend has 7 crayons. How many crayons in all? 11 + 7 = ? To make friendlier numbers, take 1 away from 11 to get 10. Then move 1 to the 7 to get 8. 10 + 8 = 18. There are 18 markers in all.
Find how many crayons in all. You have 11 crayons. A friend has 7 crayons. How many crayons in all? 11 + 7 = ? To make friendlier numbers, take 1 away from 11 to get 10. Then move 1 to the 7 to get 8. 10 + 8 = 18. There are 18 markers in all.
Find how many flowers in all.
You have 8 red flowers and 9 blue flowers. How many flowers in all? Use a double fact: 8 + 8 = 16. 8 + 9 is one more, so 8 + 9 = 17.
Find how many flowers in all. You have 8 red flowers and 9 blue flowers. How many flowers in all? Use a double fact: 8 + 8 = 16. 8 + 9 is one more, so 8 + 9 = 17.
Find how many mice are left.
There are 24 mice in a basket. 11 mice leave. How many are left? Find 24 – 11. It is easy to subtract 10. 11 is 10 and 1 more. 24 – 10 = 14. 14 – 1 = 13. There are 13 mice left.
Find how many mice are left. There are 24 mice in a basket. 11 mice leave. How many are left? Find 24 – 11. It is easy to subtract 10. 11 is 10 and 1 more. 24 – 10 = 14. 14 – 1 = 13. There are 13 mice left.
Towers
There is a tower of 20 blocks. You add stacks of 10 blocks on top. To add groups of 10 you can skip count by 10. 20 + 10 = 30. To add 34 + 50, skip count by 10. Start at 34, then jump to 44, 54, 64, 74, 84. So, 34 + 50 = 84.
Towers There is a tower of 20 blocks. You add stacks of 10 blocks on top. To add groups of 10 you can skip count by 10. 20 + 10 = 30. To add 34 + 50, skip count by 10. Start at 34, then jump to 44, 54, 64, 74, 84. So, 34 + 50 = 84.
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