Units and Conversion

Metric units are a system of measurement used in the United Kingdom and many other countries. For length, we use millimetres (mm), centimetres (cm), metres (m), and kilometres (km). Millimetres are tiny, centimetres are used for smaller objects, metres for larger objects or distances, and kilometres for long distances.

For mass (how heavy something is), we use grams (g), kilograms (kg), and tonnes (t). Grams are for light items, kilograms for heavier items (like a bag of sugar), and tonnes for very heavy items (like a car).

For capacity (how much liquid something can hold), we use millilitres (ml) and litres (l). Millilitres are for small amounts of liquid (like medicine), and litres are for larger amounts (like a bottle of juice).

To convert between metric units, we multiply or divide by powers of 10. For example, to convert a larger unit to a smaller unit, you multiply. To convert a smaller unit to a larger unit, you divide.

Imperial units are an older system of measurement still sometimes used in the UK, especially for certain things like road signs (miles) or milk (pints). We often need to know the approximate relationship between metric and imperial units.

Time is measured in seconds (s), minutes (min), hours (hr), days, weeks, months, and years. These units help us organise our lives and measure durations.

To convert between units of time, we use specific conversion factors. For example, there are 60 seconds in 1 minute, 60 minutes in 1 hour, and 24 hours in 1 day.