Question

How do i multiply this ? 320.7 million x 72.36 million ? do i have to write out all the zeros?

Answer 1

No you don't have to write all the zeros we use a technique that is called exponents and index

Explanation:

`320,700,000= 3.207 xx 10^8`

`72,360,000= 7.236 xx 10^7`

now, multiplying the above numbers using power index laws

`(3.207 xx 10^8) xx (7.236 xx 10^7)`

To muliply with the same bases the exponents (powers) are added up like:
`10^8 xx 10^7= 10^(8+7)= 10^15`

and simply multiply the rest using arithmetic
`3.207 xx 7.236 = 23.205852`

Thus, the answer will be
`23.205852 xx 10^15`

Which is written as `2.320582xx10^16`

Answer 2

`23,205.852 " million"`

or

`23.205852 " billion"`

Explanation:

No, you do not need to write all the zeros.

The question was asked with millions in words, so you can just multiply and answer in millions as well.

`320.7` million `xx 72.36 " million"`

`= (320.7 xx72.36) " million"`

`=23,205.852 " million"`

This can now also be read as:

`23.205852 " billion"`