0.0042
to convert this to standard form
there are 4 figures after the decimal points
this indicate ten of thoudsandth which is 1/10000
the actual figure after the zeros is 42
therefore, 42 x 10^-4
4.2 x 10^1 x 10^-4
4.2 x 10^1-4
4.2 x 10^-3
The answer is 4.2 x 10^-3
