Splitting numbers into parts.
Use this strategy when trying to solve addition and subtraction problems with big numbers. E.g. 72 - 24 = ___
http://www.youtube.com/watch?v=_RoXjTrMKOQ
Jumping the number line and tidy ten's.
Use this strategy when trying to solve addition and subtraction problems with an unknown number. E.g. 18 + ___ = 72
18 + 2 = 20, then 20 + 50 = 70 then 70 + 2 = 72
so, 18 + (2 + 50 + 2) = 72
So 18 + 54 = 72
Making tidy 10's.
8 + 4 = ?
Steal 2 from the 4 and add it to the 8 to make 10.
=> 8 + 2 = 10
Then add the remaining 2 to make 12.
=>10 + 2 = 12