Inches and Feet

There is a second set of length units. They work in exactly the same way.

The small one is the inch.

Inch is a unit of length, a little longer than your thumb is wide.

Twelve inches make a foot

The bigger unit is the foot. One foot is 12 inches.

Same rules as before

Line the end up with 0. Read the far end. Nothing about measuring has changed.

Inches and feet

Twelve inches make one foot. That is the fixed relationship for this pair, just as 100 centimetres make a metre. Inches are used for small things and feet for room-sized things, exactly the same division of labour as centimetres and metres.

Why there are two systems at all

Centimetres and metres are metric; inches and feet are customary. Different countries settled on different systems for historical reasons and both are still in use. You do not need to convert between them in Grade 2 — you only need to notice which system a ruler is showing, because many rulers have both, one along each edge.

Benchmarks for inches

The top joint of your thumb is about one inch. A standard sheet of paper is about 11 inches long. Your own foot at this age is not one foot long yet — the unit is named after an adult foot, which is a nice reminder that units began as body parts before anyone standardised them.