Subtraction by compensation means taking away more than you need and then adding some back. It can be quite an effective way to subtract.

Subtraction by decomposition is the way most adults are familiar with and is the way that children will ultimately use for larger numbers. Here is an introductory exploration of the idea.

Speedy addition and subtraction of 100 from 3-digit numbers.

Today we will look at the written method of subtraction, subtracting a 2-digit number from a 3-digit number including having to make an exchange.