7. Measurement

Lesson

Can you add multiple numbers together?

Solve 40 + 20 + 3.

Worked Solution

Idea summary

When adding numbers we can use a number line or add digits by place value.

The perimeter of a shape is the length around the outside of the shape.

If a shape is made up of unit squares, we can use those to count the distance around the outside of the whole shape. We count the outside edges of every unit square, making sure we include the whole outside of our shape.

Find the perimeter of the shaded region shown, where each square has a length of 1 unit.

Worked Solution

Idea summary

To find the perimeter we count the edge of every unit square, around the outside of our shape.

2D shapes are also known as polygons, and we've seen some of these shapes before. This video looks at how to work out the perimeter of any polygon.

Find the perimeter of the figure shown.

Worked Solution

Idea summary

It doesn't matter what shape our polygon is, as long as we add the length of every side, we can work out the perimeter.

We must also write the unit of measurement with our answers, such as \text{cm, m, mm}, or \text{km}.