Basic probability goes like this: # Of Successes/# Of Outcomes. In a 52 card deck, there are 52 possible cards (outcomes) you can select. How many of those cards are hearts? How many of those cards are less than (but not equal to) four. How many of those cards are both less than four AND hearts?

The probability of getting two hearts OR two cards less than four is P(Two Hearts) + P(Less Than Four) - P(Two Hearts AND Less Than Four).

See if you can suss out the problem now, and see if you get why why subtract that last probability from the combination of the two.