How do you convert 7.121 x 10^9 into expanded notation?

Aug 1, 2018

7,121,000,000

Explanation:

To expand out $7.121 \cdot {10}^{9}$, we can imagine moving the decimal place 9 times to the right and filling in any spaces with zeros:

$7.1210000000$ (0 times)
$71.210000000$ (1 time)
$712.10000000$ (2 times)
$7121.0000000$ (3 times)
$71210.000000$ (4 times)
$712100.00000$ (5 times)
$7121000.0000$ (6 times)
$71210000.000$ (7 times)
$712100000.00$ (8 times)
$7121000000.0$ (9 times)

To check, we know that ${10}^{9}$ is a billion, so we expect the number to be in the billions and checking just by how many commas we add supports that.