Find the number of significant numbers in 2.005

Find the number of significant figures in 0.005.

The number of significant figures in 0.0035 is

The number of significant figures in 0.0009 is

The number of significant figures in 0.400 is

The number of significant figures in 0.007 is

The number of significant figures in 3400 is

The unit of measurement is mm. If the measure is 4.2 cm, then find the number of significant figures in he measurement.

The number of significant figures in 0.07 is

What is the number of significant figures in 0.310xx10^(-2)