Number – addition and subtraction

Subtracting 3-digit numbers

Take one number up to 999 away from another, borrowing a ten or a hundred where you need to.

Subtracting in columns works like adding: ones first, then tens, then hundreds. The trouble comes when a column has too little to take from.

Borrow from next door

If the top digit is smaller than the one below it, borrow ten from the column to its left. That column is then worth one less.

Worked example

What is 472 - 128?

  1. Ones: 2 is smaller than 8, so borrow a ten. The 2 becomes 12 and the 7 becomes 6.

    Ten ones have moved across from the tens column.

Try it together

Let us work out 452 - 128 together.

Ones first, and the ones column will need a borrow.

    1.The ones are 2 take away 8, which we cannot do. Borrow a ten, then work out 12 - 8.

    Have a go

    Have a go on your own: 365 - 142 = ?

    Hint: No column needs to borrow in this one.

    Ready to practise?

    Eight questions on what you have just read. Nothing is timed, and you can play as many times as you like.

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