Mental addition strategies
Answers are for parents and teachers.
1
Write the doubles from 1 + 1 to 10 + 10.
2, 4, 6, 8, 10, 12, 14, 16, 18, 20
2
Solve 8 + 9 and 6 + 5 with doubles.
8 + 9 = 17 and 6 + 5 = 11
3
Count on to solve 5 + 13 and 16 − 13.
18 and 3
4
Add 10 to each number: 3, 8, 11, 15.
13, 18, 21, 25
5
Take away 10 from each number: 20, 17, 14, 10.
10, 7, 4, 0