equal operators

(*=, //=, +=, -=, %=)

          +=           Addition assignment        x += 4;     x = x + 4;
          -=           Subtraction assignment     x -= 4;     x = x - 4;
          *=           Multiplication assignment  x *= 4;     x = x * 4;
          /=           Division assignment        x /= 4;     x = x / 4;
          %=           Remainder assignment       x %= 4;     x = x % 4;