Length — centimeters and meters
You already know:
- 1 cm is about the width of your fingertip.
- 1 m is about your shoulder height.
1 m = 100 cm.
That's the only conversion fact you need.
Converting m to cm
Multiply meters by 100, then add the leftover cm.
3 m 40 cm = 3 × 100 + 40 = 340 cm.
2 m = 200 cm.
1 m 5 cm = 105 cm.
Converting cm to m and cm
Take whole hundreds out — those are full meters. The rest stays in cm.
250 cm = 2 m 50 cm (because 250 = 2 × 100 + 50).
400 cm = 4 m 0 cm = 4 m.
187 cm = 1 m 87 cm.
Reading a ruler
A ruler has three sizes of ticks:
- Big ticks with numbers — whole centimeters.
- Medium ticks in the middle — half centimeters (5 mm).
- Small ticks between them — millimeters.
If the object ends at the 5th big tick, it's 5 cm.
If it ends 2 small ticks past 5 cm, it's 5 cm 2 mm = 5.2 cm.
Comparing lengths
To compare, convert both to the same unit.
1 m vs. 80 cm → 100 cm vs. 80 cm → 1 m > 80 cm.
250 cm vs. 2 m 60 cm → 250 vs. 260 → 250 cm < 2 m 60 cm.
Try it
Summary
- 1 m = 100 cm.
- m → cm: multiply by 100 and add cm.
- cm → m+cm: take whole hundreds out.
- To compare: convert to the same unit.