Foundation and Higher · converting units
Converting units.
Multiply or divide?
and why 1 m² is not
100 cm²
one question decides it —
More or fewer?
smaller unit: more of them, so ×
bigger unit: fewer of them, so ÷
step 1 of 4
Length and mass
1. Metres are smaller: more of them, so ×.
2. Kilograms are bigger: fewer, so ÷.
✓ Ask: should the number get bigger?
3.2 km → m
1 km = 1000 m
3.2 × 1000 = 3200 m
450 g ÷ 1000 = 0.45 kg
step 2 of 4
Time is not decimal
1. 0.4 of an hour is not 40 minutes.
2. An hour has 60 minutes: 0.4 × 60 = 24.
✓ Going back: 24 ÷ 60 = 0.4
2.4 hours
= 2 hours + 0.4 of an hour
0.4 × 60 = 24 minutes
2 h 24 min not 2 h 40
step 3 of 4
Area units
1. A 1 m square is 100 cm along each side.
2. Area = 100 × 100 = 10 000 cm².
✓ 1 m² = 10 000 cm², not 100
step 4 of 4
Volume units
1. Volume: multiply by 100 three times.
2. Litres link volume to capacity.
✓ Area: square it. Volume: cube it
1 m3 = 100 × 100 × 100 cm3
= 1 000 000 cm3
1 litre = 1000 cm3
1 ml = 1 cm3
converting units —
To a smaller unit
multiply
Area and volume
square or cube the factor
Time works in 60s.
0.5 hours is 30 minutes, not 50.
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