Why do you divide by 100 when converting centimeters into meters?

Answer 1

The milli- prefix means 1/1000 (one thousandth) → 1 mm = 1/1000 m

The centi- prefix means 1/100 (one hundredth) → 1 cm = 1/100 m

But in equivalent fractions 1/100 = (1×10)/(100×10) = 10/1000 = 10 × 1/1000

→ 1 cm = 1/100 m = 10/1000 m = 10 × 1/1000 m = 10 mm

Thus for every 1 cm there are 10 mm,

but this can also be written as for every 10 mm there is 1 cm.

Thus to convert cm to mm multiply by 10; and

to convert mm to cm divide by 10.

To help remember whether to multiply of divide:

When going from a bigger unit (cm) to a smaller unit (mm) there will be more of them so multiply

When going from a smaller unit to a bigger unit (you are clumping them together and so) there will be fewer of them so divide.

Answer 2

You have to divide because millimeters are smaller than centimeters.

1mm = 0.1000000 cm
Formula:

cm = mm
------
10.000

Millimeter equals 1/1,000 of a meter Cenimeter equals 1/100 of a meter

Answer 3

1 cm = 10 mm so you need to multiply by 10. But, if you don't like multiplication, you could always divide by 0.1 instead.