# How do you simplify and write (4 times 10 ^ 8) + ( 2 times 10 ^7) in scientific notation?

$4.2 \cdot {10}^{8}$
$4 \cdot {10}^{8} + 2 \cdot {10}^{7}$
=$40 \cdot {10}^{7} + 2 \cdot {10}^{7}$
=$42 \cdot {10}^{7}$
=$4.2 \cdot {10}^{8}$