Physics question below?

Question

A metal sphere has a charge of +6.0 µC. What is the net charge after 6.00 1013 electrons have been placed on it?

Answer 1

An electron has a charge of -1.60 x 10^(-19) C. Multiply this value by the number of electrons being added, 6.00 x 10^13, to get a net charge being added.

[-1.60 x 10^(-19) C] * [6.00 x 10^13]

-0.0000096 C = -9.6 µC

Just add the value to 6 µC to get a value of -3.6 µC after the electrons are added.