Lesson

How confident are you that you can subtract numbers down your page, using a vertical algorithm ?

Find the value of 95 -51.

Worked Solution

Idea summary

You might notice that sometimes the standard algorithm is called the 'vertical algorithm'. Let's think about why. When we use the standard algorithm, we line our numbers up in 'vertical' place value columns.

Let's see what we need to do when we don't have enough in one of our place value columns to subtract.

Find the value of 58 - 29.

Worked Solution

Idea summary

We always start from the ones place, when we work down our page. If we don't have enough ones to subtract, we need to trade from the tens place.

uses mental and written strategies for addition and subtraction involving two-, three-, four and five-digit numbers