I can't interpret what he's done. A guess would be that he thinks ^ is the same thing as *. You have correctly stated that 4^4 = 256 and then you just add on the 1/2. You mean 4*4*4*4 and he means 4*4. That's a hard error to correct, but do your best.
5 percent of 140 is 7. You can think of this as taking ten percent of 140.0 by moving the decimal point one place to the left, 14, and then since 10 divided by 2 is 5, divide that by 2 and you get 7.
