# How do you multiply 37,000,000 * 7,100,000 and write the answer in scientific notation?

Apr 2, 2015

First you write both numbers in scientific notation:

$37000000 = 3.7 \cdot {10}^{7}$ because you had to move the decimal point 7 places to the left to keep just one non-zero digit in front of it.
$7100000 = 7.1 \cdot {10}^{6}$ (6 places to the left)

Multiply the numbers and add the $10$powers:
$3.7 \cdot 7.1 \cdot {10}^{7 + 6} = 26.27 \cdot {10}^{13}$

To normalise this we need to move the decimal point one to the left and so the power goes up by one. We also want to round to two significant digits, as that was what's in our original numbers:

$26.27 \cdot {10}^{13} \approx 2.6 \cdot {10}^{14}$