Question

m change into dm what should be do

Answer 1

Multiply the given number by 10.
1 m = 10 dm

Answer 2

HOLA friend!!
Rajdeep here....

Do you know about the metric table?
Kilometre
Hectometre
Decametre
Metre
Decimetre
Centimetre
Millimetre

Now, if dm means decimetre, just multiply the given value in metres by 10.
If dm means decametre, divide the given value in metres by 10.

Thanks!!