Length

How long, tall or far something is. Measured in metres, centimetres, millimetres and kilometres in most of the world, and in inches, feet and miles in a few places.

Depth 1 · Foundation

You know the metre and where it came from, and use centimetres, millimetres and kilometres for small and big lengths.

Depths of understanding

1
Foundation
You know the metre and where it came from, and use centimetres, millimetres and kilometres for small and big lengths.
Opens after
UnitsThe metre is a unit with a standard, so it helps to know what units and standards are first.
2
Deeper
You know the inch, foot and mile, and roughly how they compare with metric lengths.
Master depth 1 first

Your path here

What's still between you and Length, depth 1, in the order you can learn it.

Builds on

UnitsThe metre is a unit with a standard, so it helps to know what units and standards are first.

Opens up

Makes these deeper

Once you know Length, come back to these — they'll mean more.

Unit conversionDepth 2To change miles and inches into metric units, first you need to know what miles and inches are.