Measurement and units — introduction

Measurement and units — introduction

Measurement and units

Last year you compared lengths and used cm and m. This year you go further:

  • Length: convert between cm and m (and read a ruler).
  • Weight: convert between g and kg.
  • Volume: convert between ml and l.
  • Compare measurements that use different units.

Why three quantities?

Length is how long something is. Weight (more precisely, mass) is how heavy it is. Volume is how much liquid fits in.

Each has small units (for tiny things) and big units (for big things):

QuantitySmall unitBig unitConversion
Lengthcmm1 m = 100 cm
Weightgkg1 kg = 1000 g
Volumemll1 l = 1000 ml

Notice — for weight and volume the multiplier is 1000; for length it's 100.

What you'll learn

  • Length — cm and m, including conversions.
  • Weight — g and kg.
  • Volume — ml and l, plus comparing units.
  • For parents — how to help at home.

Try it

Summary

  • Three quantities: length, weight, volume.
  • Each has a small and a big unit: cm/m, g/kg, ml/l.
  • 1 m = 100 cm, 1 kg = 1000 g, 1 l = 1000 ml.
Length →