Converting from a smaller unit to a larger one

When you go from a smaller unit (mm, cm) to a larger one (m, km), you always divide. The reason: a larger unit is a longer measuring stick, so the same distance fits into fewer of them.

The rule

To convert from a smaller unit to a larger unit, divide by the conversion factor.

Metric examples

Conversion	Factor	Calculation
m → km	1 000	$5000 m = 5 000/1 000 = 5 km$
cm → m	100	$700 cm = 700/100 = 7 m$
mm → dm	100	$400 mm = 400/100 = 4 dm$
mm → cm	10	$90 mm = 90/10 = 9 cm$
cm → km	100 000	$200000 cm = 200 000/100 000 = 2 km$

Imperial examples

Conversion	Factor	Calculation
in → ft	12	$60 in = 60/12 = 5 ft$
ft → yd	3	$21 ft = 21/3 = 7 yd$
in → yd	36	$144 in = 144/36 = 4 yd$
ft → mi	5 280	$10560 ft = 10 560/5 280 = 2 mi$

Whole-number results only

To get a whole number out, the input must be a multiple of the conversion factor. Our exercises always pick the input that way, so you can practise the calculation without having to deal with decimals.

In practice it means:

$4000 m$ converts cleanly to $4 km$ ✓
$4500 m$ would give $4.5 km$ — not a whole number, so it would not appear in this exercise.

Quick mental check

A useful trick: count the zeros in the conversion factor and remove the same number of zeros from the input.

$5000 m \div 1000 = 5 km$ — three zeros disappear.
$700 cm \div 100 = 7 m$ — two zeros disappear.

If the input does not end in enough zeros, the result will not be a whole number — and you should check the input again.

Common pitfalls

Forgetting which direction divides. Smaller → larger means you can fit fewer of the longer sticks, so the count gets smaller — and that means dividing.
Misreading factors. $1 km$ is $1000 m$ , not $100$ . The big jump in the metric system is exactly here.
Imperial mile: 1 760 yards is the trickiest factor. It is worth memorising.