# How do you simplify and write (2.1 times 10^-5)(3 times 10^-2) in scientific notation?

$6.3 \times {10}^{- 7}$
$2.1 \times 3 = 6.3$
${10}^{- 5} \times {10}^{- 2} = {10}^{- 5 + - 2} = {10}^{- 7}$