How do you express a number lesser than 1 in scientific notation?

Answer 1

You multiply it by powers of ten until you get a number that lies in the interval [1,10). The exponent of the ten in the scientific notation would be the negative of that power.

For example

0.0034 needs to be multiplied by 103 to get 3.4

so 0.0034 = 3.4*10-3

Another way to look at this is as follows:

Remember that 10ax10-a = 1 for all a

Then 0.0034 = 0.0034x103x10-3 = 3.4x 10-3