Lesson

How did you find adding numbers, using the standard algorithm ?

Find the value of 41 + 56.

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 try some subtraction problems, using the standard algorithm. We use place value models to help us, so you might like to have some handy as you watch the video.

Find the value of 95 -51.

Worked Solution

Idea summary

When we solve problems using an algorithm, we have to line up our digits by place value. With subtraction, we always put the total at the top, and the number we are subtracting, below.

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