(2.053 x 10^4) - (7.956 x 10^3) The power of 10 tells you how many places to move the decimal. If it is a positive number, move the decimal right. If it is a negative number, move it left. (2.053 x 10^4) - (7.956 x 10^3) Move the decimal of 2.053 4 places right and get 20530 because 10 is to the 4th power. Move the decimal of 7.956 3 places right and get 7956 because 10 is to the 3rd power. So we subtract: 20530-7956 = 12574. This is 1.2574 x 10^4 because you have to move the decimal 4 places to get 12574, Edwin