This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
I don't know why your'e asking for a sum. Anyway I will assume that the 10-3 is supposed to be 10^{-3

When the power of 10 is negative we move it to the left at this case 3 times.

We move the decimal point 3 to the left and we get: