when simplifying a fraction, whatever you do to the top has to be the same as what you do to the bottom. if nicholas simplified the numerator by 5 he has to simplify his denominator by 5. if did that correctly, 20/5=4 and 30/5=6. however, he can still simplify. taking the new fraction 4/6 you can divide both the numerator and denominator by 2. 4/2=2 and 6/2=3. nicholas would now have the fraction 2/3