# How do you multiply (4.7 x 10^-8) (7.6 x 10^3)?

You can first multiply $4.7 \times 7.6 = 35.72$ and then deal with the powers of ten remembering that ${a}^{m} \cdot {a}^{m} = {a}^{m + n}$;
${10}^{- 8} \cdot {10}^{3} = {10}^{- 8 + 3} = {10}^{- 5}$
$35.72 \times {10}^{- 5}$ rearranged to have:
$3.572 \times {10}^{- 4}$ by moving the decimal point to the left and changing, as a consequence, the exponent of $10$ of 1 unit.