First, I would use a scientific calculator. On that calculator, there is either an “EE” key, an “EXP” key, or a “x10^x” key. There will only be one not all three. I will assume it is “EE” because that is the most popular. This key abbreviates “times ten raised to the.” Thus, if I wanted to enter the number 1.43×10^-23 in the calculator, I would enter:

1.43
then hit the “EE” key
then enter
23
then hit the “+/-” key

The display will read 1.43 with a small -23 in the upper right-hand corner. That means 1.43 times ten to the -23.

So, in the given problem, you would enter it in the following way:

118.9
then hit the “X” key
1.67
then hit the “EE” key
24
then hit the “+/-” key

then hit equals.

The display will read 1.98563 with a small -22 in the upper right-hand corner.
That means 1.98563 x 10^-22

If you want to know how to do it on paper, you just need to realize that the “times ten to the power” can be separated. For example, in:

118.9 x 1.67 x 10^-24,

you can just do the numbers first:

(118.9 x 1.67) x 10^-24

198.563 x 10^-24

Then convert so that the decimal point is just to the right of the first number:

1.98563×10^-22

If the problem has 2 numbers in scientific notation, just group the ten powers together. For example:

1.23 x 10^-6 times 1.34 x 10^-12

1.23 x 10^-6 x 1.34 x 10^-12

(1.23 x 1.34) x (10^-6 x 10^-12)

1.6482 x 10^-18