Always reduce the fractions. 2/10 has a similar factor, which is 2. It reduces to 1/5. And 4/8 has a similar factor which is 4, so it reduces to 1/2. Which means 1/2 is greater than 1/5 which means 4/8 is greater than 2/10. 2/5 is less than 1/2 because the decimal form is .4 to .5. So 2/5 is less than 4/8 and since 2/10 reduces to 1/5, 2/5 is greater.