Converting units: the metric staircase
Walk up and down a staircase of metric units to convert road lengths, milk and rice between km, m, cm, L, mL, kg and g.
Core concept
In short: Change between units like cm, m and km by multiplying or dividing by 10, 100 or 1000.
Each metric unit is 10 times the next smaller one, so converting means multiplying or dividing by 10, 100 or 1000
Topic: Measurement and unit conversion
Metric units go in steps of ten: kilo, hecto, deca, the base unit (metre, gram or litre), deci, centi and milli. Each step down the staircase is a unit ten times smaller, so the same amount needs ten times more of it. Going down, multiply by 10 for each step; going up, divide by 10 for each step. The road to the school is 2.5 km; a packet of milk holds 500 mL; a sack of rice weighs 25 kg.
What you will learn
- Convert between metric units of length, mass and capacity.
- Decide whether to multiply or divide, and by 10, 100 or 1000.
- Use conversions in everyday problems.
Before you start
- Multiplying and dividing by 10, 100 and 1000.
Materials
- A measuring tape, a 1 L bottle and a kitchen scale
Equipment
- A ruler marked in cm and mm
Procedure
- Tap the chip to choose length, mass or capacity, and − or + to change the amount.
- Tap ▸ under a step to start from that unit, and ◂ under a step to convert to it.
- Count the steps: down means multiply, up means divide.
- Convert 2.5 km to m, 750 mL to L, 1500 g to kg and 25 cm to mm, and record each.
How this simulation is simplified
- Only metric units are used.