1.NBT.6, 2.NBT.5
Add multiples of 10 within 40
Place value within 40 (2)
Subtraction sentences within 10
Add & subtract multiples of 10 within 40
Subtract multiples of 10 from mult of 10
Subtract mult of 10 from 2-digit numbers
Subtract multiples of ten from 2-digit numbers.
