30cm=_____mm
1 cm = 10 mm
30 cm = ______ mm
To convert centimeters to millimeters, you multiply the centimeter value by 10 because there are 10 millimeters in 1 centimeter.
So, to convert 30 cm to mm, you would do:
30 cm * 10 = 300 mm
Therefore, 30 cm is equal to 300 mm.