Line up the decimals when you are adding or subtracting. Add extra zeroes when there is not place value match.


  • estimate: a number close (not exact) to an amount or value, a good guess using what you know
  • rounding:change an exact number to an easy to use number that is very close to the exact number 656 to hundreds = 700 
  • compatible numbers: pairs of numbers you can easily work with in your head

Interactive Math Games:




Printable Practice: