It may help to think of these numbers as fractions.

$0.04 = \frac{4}{100}$

Can you write 0.7 as a fraction?

$(0.04)(0.7)= \left ( \frac{4}{100} \right )\left ( \frac{7}{10} \right )=\frac{28}{1000}$

How can you write this as a decimal?

Refer to the steps in part (a).