I'm having trouble understanding how you would divide the charge of an object by its mass. How can you divide a charge - I mean isn't it either positive or negative? I understand that the charge is equal to the 6.25 × 1018 so an electron would have a charge of −1.602 x 10-19. I guess my question is, how can you divide a charge by mass - isn't that like dividing apples and oranges? I understand that mass and energy are related, but I don't understand how you can divide a charge with a mass.