In thinking about answer choice (1), first decide which numbers, when squared, will give a unit's digit of 4. The numbers 2, 8, and 12 meet this condition. Now subtract 4 from each of them, to get the value of n. So we are left with 8 and 12 as possible answers. Since there are 2 possible solutions, answer choice (1) by itself is not enough. To understand answer choice (2), look for numbers that, when squared, have a unit's digit of 1. The possibilities are 1, 9, and 11. Now subtract 3 and we get 6 and 8. Since 8 is the answer in both (1) and (2), it is the only solution to the problem, and we need both statements to solve the question.