Adding Strategies

The Nines Trick
Any number plus 9, is one less than the digit in the ones column plus 10 See how this works in the following examples:

8+9=17 - one less than 8 is 7 plus 10 more equals 17

15+9=24 - one less than 5 is 4 plus 10 more with the tens is 24

Make a Ten
Make ten and then add the remaining amount. For example: 8+6 You think oh I know 8 and 2 more make ten. I will take 2 from the 6 to make ten and I have 4 left over so 10 + 4 = 14. therefore 8+6 = 14

Doubles
Learning the doubles is like counting by twos. 1+1 is 2, 2+2 is 4, 3+3 is 6, 4+4 is 8, 5+5 is 10 and so on.

Nearly Doubles
Once you know the doubles, you can expand that knowledge to doubles plus or minus one. For example, if you know 6+6 is 12 then you can know that 6 +7 is 12 +1 which is 13. Another examples is 7+8 I know 7+7 is 14 so 7+8 is 14 +1 which = 15 It can also be the opposite, such as 8+9 I know 9 +9 is 18 so 8+9 = 18-1=17