Even Numbers Are Doubles

Write an even number as two equal addends: 18 = 9 + 9.

Warm-up, learn, try it together, practice, then a quick check. About 15 minutes.

What children learn in Level 77

Every even number can be split into two equal groups. 18 cookies make two rows of 9.
So every even number is a double! 12 is 6 plus 6. 20 is 10 plus 10.
Odd numbers can't do that. 9 makes 4 and 5, which aren't equal. There's always one extra!
To write an even number as a double, find half of it: 14 equals 7 plus 7.

Georgia's K-12 Mathematics Standards:

2.NR.3.1 — Determine whether a group (up to 20) has an odd or even number of objects. Write an equation to express an even number as a sum of two equal addends.