Subtraction by "Regrouping"

(Also called "borrowing" or "trading")

To subtract numbers with more than one digit:

Smaller Number - Bigger Number

subtract before borrow

But what if a column has a smaller number on the top?

How do we do 2 - 5 ?

The Solution: Make the "2" larger by "regrouping" (press arrow button):

In 32:

  • the "3" means 3 tens,
  • the "2" means 2 ones,

So we:

  • reduce the 3 by 1
  • increase the 2 by 10

And we get:

  • 2 tens,
  • 12 ones

And here is how to do it with a pencil and paper:

We use this method whenever a column has a smaller number on top, as in this example:


But we can't regroup from zero ...

But we can make a "0" into a "10" by regrouping it first, them carry on normally, like this:


Now, you can practice with these Subtraction Worksheets