The Metric System summary

Key learning points

• Length: $1\,\mathrm{km}=1000\,\mathrm{m}$, $1\,\mathrm{m}=100\,\mathrm{cm}=1000\,\mathrm{mm}$.
• Mass: $1\,\mathrm{kg}=1000\,\mathrm{g}$; capacity: $1\,\mathrm{l}=1000\,\mathrm{ml}$.
• Convert to a single unit before calculating area or volume.
• Estimate first so a slipped decimal place stands out.

Worked example 1 — Length conversion

Convert $2.5\,\mathrm{km}$ to metres.

Working

$1\,\mathrm{km}=1000\,\mathrm{m}$.

Worked example 2 — Mass

Convert $450\,\mathrm{g}$ to kg.

Working

$1\,\mathrm{kg}=1000\,\mathrm{g}$.

Worked example 3 — Capacity

Convert $1.2\,\mathrm{l}$ to ml.

Working

$1\,\mathrm{l}=1000\,\mathrm{ml}$.

Worked example 4 — Area units

Side $30\,\mathrm{cm}$. Area in $\mathrm{m}^2$?

Working

Convert to metres first.

Scaffolded Learning Sheet and answers (PDFs)

This page is a short, searchable overview for revision and search engines. Use the Scaffolded Learning Sheet first, then the Answers PDF for a full written solution. The printable PDFs remain the main classroom resource.