How do you convert 4500 mm to m?
When converting metric units, we operate in powers of 10 (essentially, we're moving the decimal point in the number we're working with).
We're starting with 4500 millimetres and we're looking for the equivalent number of metres.
Metres are bigger than millimetres, and so we'll expect the number to become smaller (for a given length, the shorter the length of our measure, the more we need of them and the longer our measure, the fewer we need.)
Starting with 4500 millimetres, the next biggest measure is centimetres. Centimetres are 10 times bigger than millimetres, so we need 10 times less:
We can do this again with the next biggest unit of measure, the decimetre:
And the next biggest measure is the metre: