Addition

Add Within 20 Using Make Ten

Add 8 + 7 using the make-ten strategy: split 7 into 2 + 5, make 8 + 2 = 10, then add 5 to get 15.

Example

Add 8 and 7 by making a ten first.

highlighted = computed this step

Step 1 — Set up

Start with the addition sentence.

8+7=□8+7=\square
Start with 8 + 7make 107 to split

Step 2 — Find what makes ten

Start with 8; it needs 2 more to make 10.

8+2=108+\hl{2}=10
8 needs 2 more to make 10make 107 to split2 to make ten

Step 3 — Split the second addend

Split 7 into 2 and 5.

7=2+57=\hl{2}+\hl{5}
Split 7 into 2 and 5make 10leftover 510 filled

Step 4 — Make ten

Make ten: 8 + 2 = 10.

8+2=108+2=\hl{10}
8 + 2 makes 10make 10leftover 510 filled

Step 5 — Add the leftover

Add the leftover: 10 + 5 = 15.

10+5=1510+5=\hl{15}
10 + 5 = 15make 10leftover 510 filled+ 5 more

Step 6 — Result

Read the complete answer: 8 + 7 = 15.

8+7=158+7=15
8 + 7 = 15make 10leftover 510 filled+ 5 more
make-ten Split one addend to bring the other up to 10, then add the leftover. For 8 + 7: 8 needs 2 more to reach 10, so split 7 into 2 + 5. Then 8 + 2 = 10 and 10 + 5 = 15.