Question

Which is the best estimate for (6.3x10^-2)(9.9x10^-3) written in scientific notation?

Answer 1

it should be 6.237*10^-4

Answer 2

`6 * 10^(-4).`

Explanation:

We are given expression
`(6.3 * 10^(-2))(9.9* 10^(-3))`.

In order to multiply above given expression, we need to multiply 6.3 by 9.9 first.

On multiplying 6.3 by 9.9 , we get 62.37.

Now we would multiply
`10^(-2) \ by \ 10^(-3).`

Therefore,

`10^(-2) * 10^(-3)= 10^(-2-3)= 10^(-2-3) = 10^(-5).`

Therefore,

`(6.3 * 10^(-2))(9.9* 10^(-3)) =62.37 * 10^(-5)`

Again
`62.37 * 10^(-5)` could be written as
`6.237 * 10^(-4)`.

Now,
`6.237 * 10^(-4)` could be round to
`6 * 10^(-4).`

Therefore, correct answer is
`6 * 10^(-4).`