Barry M. answered 01/15/20
Professor, CalTech Grad; Many Years Tutoring Math, SAT/ACT Prep, Chem
I assume you mean 103 and 106.
Then multiplying 4.56 X 3.1 = 14.136
And multiplying the powers of ten gives 109, since multiplying exponential numbers with the same base is accomplished by adding the exponents.
So 14.136 X 109 is a result, but to write in proper scientific notation, the decimal part of the number needs to be between 1 and 9.9999. The value is maintained by dividing the decimal number by 10 (moving the decimal point) while multiplying the exponent part of the number by 10 (adding 1 to the power)
The result is 1.4136 X 1010.
Finally, round to the correct number of sig figs. The rule for multiplying requires that the result should have the same number of sig figs as in the number being multiplied with the least number of sig figs. In this case, 3.1 has 2 sig figs, whereas 4.56 has 3 sig figs. So the result should have 2 sig figs.
Therefore, round to 1.4 X 1010.