One of the things that we must help children do is recognize when to use a particular strategy. For the Doubles Plus One strategy, tell the children "when the numbers are next door neighbors (the numbers are consecutive like 6 and 7) then we can use the doubles plus one strategy."
Doubles Plus Two
If a child is faced with a problem like 5 + 7, think through the same steps as Doubles Plus One except add 2 instead of one. This works for facts that have number that are separated by two.
When helping a child to recognize when to use this strategy tell them to use it "when the numbers are NOT next door neighbors, but two doors down from each other."
Plus 9 Shortcut
If your child is learning a fact like 9 + 5 these are the steps to think through:
* Think 10 + 5 = (which is much easier to add)
* Now minus 1 (Think 15 - 1 + 14)
* Now say the fact: 9 + 5 = 14
* Remind your child that you added 10 + 5 instead of 9 + 5. That's one more than you started with, so you have to take that one away to get to the correct answer.
Minus 9 Shortcut
If your child is trying 17 - 9, these are the steps to think through:
* Change the 9 to 10 ( Think 17 - 10 = 7, which is much easier to subtract)
* Now add 1 ( Think 7 + 1 = 8)
* Now say the fact: 17 - 9 = 8
* Now remind your child that you subtracted 17 - 10 instead of 17 - 9 . That's taking one more away then you started with, so you have to add that one back to get the right answer.
Minus 8 shortcut
If your child is learning 15 - 8, these are the steps to think through:
* Change the 8 to 10 (Think 15 - 10, which is much easier to subtract)
* Now add 2 (Think 5 + 2 =7)
* Say the whole fact now: 15 - 8 = 7
* Remind your child that you took two extra away when you changed to 8 to 10 in the first step, and you must add it back to get the right answer.
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