Add numbers faster with the make 10 strategy
A simple way to solve additions such as 8 + 7 without counting one number at a time.
The make 10 strategy rearranges an addition so one number becomes 10. For 8 + 7, move 2 from the 7 to the 8. The question becomes 10 + 5, and the answer is easier to see. The numbers move, but the total stays the same.
Turn 8 + 7 into 10 + 5
Move two objects to fill the group of 10. Nothing is added or removed.
Before
8 + 7
After
10 + 5
8 + 7=10 + 5= 15
First, know the pairs that make 10
These pairs are the building blocks of the strategy. Read them in either direction: 2 + 8 and 8 + 2 both make 10.
How to use the strategy for 8 + 7
The objects above show what moves. Follow the same idea with the numbers.
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Ask what 8 needs to become 10
8 + 2 = 10
Eight needs two more. That tells you how much to move from the other number.
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Split 7 into 2 and 5
7 = 2 + 5
Move the two to the eight. Five are left. You have rearranged the same numbers, so the total has not changed.
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Add 10 and the 5 that remain
10 + 5 = 15
Ten plus five is easier to see in your head. So 8 + 7 is 15.
More make 10 strategy examples
Choose the number that is closest to 10. Move only what it needs, then add the remainder.
7 + 5
7 needs 3, so split 5 into 3 + 2.
10 + 2= 12
8 + 6
8 needs 2, so split 6 into 2 + 4.
10 + 4= 14
9 + 4
9 needs 1, so split 4 into 1 + 3.
10 + 3= 13
Make 10 when adding three numbers
With three numbers, look for two that already make 10. Add that pair first, even when the numbers are written in a different order.
Addition can be regrouped without changing the total. Pairing 8 and 2 first removes the need to calculate 8 + 5 before adding 2.
Use the same idea with larger numbers
Instead of completing 10, complete the next multiple of 10 or 100. The movement is exactly the same.
Now try 9 + 6
9 + 6 = ?
What does 9 need to become 10? Move that amount from the 6, then add what remains to 10.
Show the answer Hide the answer
9 needs 1. Split 6 into 1 and 5, then move the 1: 9 + 6 becomes 10 + 5, which is 15.
Show the strategy with objects
If the movement feels abstract, place 8 coins or counters in one group and 7 in another. Leave two spaces beside the group of 8. Move two objects from the group of 7 into those spaces. You can now see one complete group of 10 and five objects left over.
Ask: How many does this number need to reach 10? This keeps attention on the useful number relationship instead of memorizing a rule without understanding it.
Try the method while you play
Open a round of one-digit addition. Whenever an answer crosses 10, complete the 10 first and then add what remains.
Questions about the make 10 strategy
Why does the make 10 strategy work?
It moves part of one addend to the other without adding or removing anything. In 8 + 7, splitting 7 into 2 + 5 gives 8 + 2 + 5. That has the same total, but 10 + 5 is easier to calculate.
When should I use the make 10 strategy?
It is especially useful when one number is close to 10, such as 7, 8, or 9. The same idea also helps you reach 20, 50, 100, or another nearby round number.
Can make 10 help with subtraction?
Yes. You can bridge through 10. For 14 - 6, subtract 4 to reach 10, then subtract the remaining 2 to get 8. This lesson focuses on addition so you can become comfortable with the movement first.