Question

Suppose you are asked to find 91,321,972×0.007004. Doing a quick estimate by rounding the numbers in scientific notation, what value would you expect the answer to be close to? (If you need a review of the estimation technique, watch the video Scientific Notation, Part 4.)

Answer 1

Answer:
`63*10^4`

we need to estimate the product of two numbers by writing them in scientific notation and rounding them off.

In scientific notation, number 91321972 can be written as
`9.1321972*10^7`

If we round this off to 1 significant figure, it would be:

`9*10^7`

In scientific notation, number 0.007004 can be written as
`7.004*10^(-3)`

If we round this off to 1 significant figure, it would be:

`7*10^(-3)`

Product of these two numbers:

`9*10^7 * 7*10^(-3)=9*7*10^(7-3)=63*10^(4)`