Question

(2.5×10−8)(9×10−10)

Express your answer in scientific notation.

Answer 1

We have given expression as


`(2.5*10^(-8))(9*10^(-10)`

Now we can multiply 2.5 and 9 and also combine exponents of 10.


`(2.5*10^(-8)) * (9*10^(-10)) = 2.5*9 * 10^(-8-10)`
=
`22.5*10^(-18)`

Now for writing it into scientific notation we have to shift decimal by one place in backward direction.
So we can write answer as


`22.5*10^(-18) = 2.25*10^(-18)* 10 = 2.25*10^(-17)`

So answer is
`2.25*10^(-17)`

Answer 2

Answer: 2.25x
`10^(-17)`

Scientific notation is used in science because the number can be vary from so much that using decimal is making it hard. The number expressed in
`10^(x)` form. Both number in the question is already in scientific notation. Then to multiply the number and keep it at scienfitic notation the calculation should be:

2.5 x
`10^(-8)`x 9 x
`10^(-10)`= 22.5 x
`10^(-18)`= 2.25x
`10^(-17)`