which is the smallest?

Question

3/10, 4/5, 1/2, or 2/3

Answer 1

converting to percentages (by division) produces the following values:
3/10 = .30 = 30%
4/5 = .80 = 80%
1/2 = .50 = 50%
2/3 = .66 = 66%
It is easy to see that 30% is the smallest value of the given choices.

You can also convert all fractions to a common denominator, but the given fractions are easy to convert in your head to percentages --- less work.

Answer 2

3/10 is the smallest

3/10,1/2,2/3,4/5