Convert 3.5 m to centimetres.
1 m = 100 cm
From metres to centimetres, the factor is 100.
3,5 × 100 = 350
I am going to a smaller unit, so I multiply: 3.5 × 100 = 350.
Result: 3.5 m = 350 cm
Back to the path
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Unit conversions: lengths, areas, capacities
Level 3 · Ages 11–13
Quick recall· Let's wake up what you already know before we start.
Recall: how many metres are there in 2 km?
m
The whole lesson
Read it again any time, including while you work through the exercises.
km, m, cm, mm, L, cL, m², cm²... Units are everywhere, and switching between them is a superpower. The key: understanding by how much we multiply or divide at each step.
For lengths, each unit jump multiplies or divides by 10: km, hm, dam, m, dm, cm, mm. The conversions to know by heart: 1 km = 1000 m, 1 m = 100 cm, 1 cm = 10 mm. To convert to a smaller unit, we multiply; to a bigger one, we divide.
For areas, surprise: each jump is worth 100, not 10! Why? A square with 1 m sides measures 100 cm by 100 cm, that is 100 × 100 = 10000 cm². So 1 m² = 10000 cm². Areas are two-dimensional surfaces: the factor 10 acts twice.
For capacities (liquids), the base unit is the litre: 1 L = 100 cL = 1000 mL. A large glass is about 25 cL, a juice carton 1 L, a teaspoon 5 mL.
A reliable three-step method: spot the starting unit and the target unit, count the factor (10, 100, 1000, 10000...), then multiply or divide depending on the direction. And always double-check: one misplaced decimal point and your swimming pool becomes a thimble!
The worked example, step by step
Convert 2 m² to square centimetres.
1 m² = 100 × 100 cm²
A square with 1 m sides is 100 cm by 100 cm: for areas, the length factor 100 acts twice.
1 m² = 10000 cm²
So 1 m² equals 10000 cm², not 100!
2 × 10000 = 20000
I multiply: 2 m² = 20000 cm².
Result: 2 m² = 20000 cm²