A percent is a number out of 100, so you'd want to multiply the denominator to get 100. In this case, 25 would have to be multiplied by 4 to get 100. To keep the fractions equal to each other, you have to multiply the numerator by the same thing. 2*4=8. Therefore, your fraction would be 8/100 or 8%
You first do 3 + 2, which would equal 5. Then, you would just do 3/5.