Definition
Metric system
The metric system measures with related units that scale by powers of ten.
What it means
Metric units fit together in tens, hundreds, and thousands. A kilometre is 1,000 metres; a centimetre is one hundredth of a metre. Because the scale follows place value, converting usually means multiplying or dividing by a power of ten—not changing the amount being measured.
Remember it
Keep the measurement; move through a base-ten unit ladder.
Example
A ribbon is 3 metres long. Since 1 metre = 100 centimetres, 3 × 100 = 300, so the same ribbon is 300 centimetres long.
Watch for
Changing units changes the number used to describe the measurement, not the actual length, mass, or capacity.
Common mix-up
Metric does not mean every conversion uses one step of 10; metre to centimetre is two steps, so it uses 100.
Exact meaning
The metric system, commonly expressed through SI units, is a measurement system in which prefixed units such as millimetres, centimetres, metres, and kilometres represent decimal multiples or parts of a unit.