Imperial units

Hello, and welcome to Myriora Maths! Road signs in the UK show miles, and milk comes in pints. These are imperial units: older units that people still use. Let's see roughly how big they are.

An inch is about two and a half centimetres: about the width of your thumb. Twelve inches make a foot, which is about thirty centimetres. And a mile is about one point six kilometres.

A pint is a bit more than half a litre. A pound is a bit less than half a kilogram. And fourteen pounds make a stone.

Here's a handy way to swap miles and kilometres. Five miles is about eight kilometres. So ten miles is about sixteen kilometres, and twenty miles is about thirty-two kilometres.

Let's try one together. Twelve inches make a foot. How many inches are in two feet? Say it out loud!

Two times twelve is twenty-four inches!

Here's a question that catches lots of people. How many inches are in three feet? Some people say thirty, as if there were ten inches in a foot. But a foot has twelve inches. Three times twelve is thirty-six inches!

Your turn! About how many kilometres is ten miles? Pick the right card. You've got twenty seconds, or pause the video. Go!

Time's up! Five miles is about eight kilometres. Ten miles is double that: about sixteen kilometres!

Quick review. An inch is about two and a half centimetres, and twelve inches make a foot. A mile is about one point six kilometres: five miles is about eight kilometres. A pint is a bit more than half a litre. Imperial units don't go in tens, so learn the numbers. See you next time!