An iron arrowhead has an initial charge of 2.100e-6 C. How many electrons are required to give it a charge of −2.82 μC? I know that e (the elementary charge) = +/- 1.602E-19 C And N is the number (or excess charge) I tried solving this problem 2 ways. The first way: (2.100E-6 - 2.82E-6)/1.602E-19 I got 4.45E12 electrons The second way I did: 2.100E-6-1.602E-19 * N = -2.82E-6 -1.602E-19 * N = -2.82E-6 - 2.100E-6 N =-4.92E6/-1.602E19 N= 3.05E25 electrons However, my homework says it's wrong I tried typing them in with a negative sign, it's wrong. I tried rounding to the nearest electrons, still wrong. What am I doing wrong? I really have no idea!