Unit Conversions
Convert freely between related standard units of measurement (time, length, area, volume/capacity, mass) using decimal notation to up to three decimal places where appropriate
What a learner can do afterwards
- Convert between area units such as cm² and m² using the square of the linear scale factor
- Perform multi-step conversions (e.g. convert 2.5 hours to seconds via minutes)
- Convert volume units such as cm³ to litres and explain the relationship
The lesson
Units come in families: length (mm, cm, m, km), mass (g, kg), time (s, min, h), and volume (mL, L, cm³). To move between units in the same family, multiply or divide by a conversion factor. For example, 1 m equals 100 cm, so multiplying a length in metres by 100 gives you centimetres.
To convert 2.5 hours to seconds, work step by step. First change hours to minutes: 2.5 × 60 = 150 minutes. Then change minutes to seconds: 150 × 60 = 9000 seconds. Going straight from hours to seconds in one jump is easy to get wrong, so build the bridge through minutes.
A square metre is 100 cm on each side, so it holds 100 × 100 = 10,000 square centimetres. Whenever you convert an area unit, square the linear scale factor first, then multiply.
Volume units connect too: 1 cm³ of water fills exactly 1 millilitre, and 1000 cm³ make 1 litre. Before you convert, find the connecting fact between the two units, then multiply or divide by it.
To convert units, find the connecting fact, work through it step by step, and square the scale factor for area.
Watch it
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.