Subtraction by "Regrouping"

(Also called "borrowing" or "trading")

To subtract numbers with more than one digit:

• write down the larger number first and the smaller number directly below it
  making sure to line up the columns!
  
• then do subtractions one column at a time like this (press play button):

Smaller Number - Bigger Number

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):

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:

Zero

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