For the first instance, 16+9 is 25 and the root of that is 5. But for the second one, we have to first find the roots. So 4+3 which equals 7. These are obviously not equal. Does this make sense? Hope that helps.
The probability is (1/6)^5 power. Since the locks are independent of each other, you can multiply the probabilities together. There are 6 possible numbers for each lock and there are 5 locks. So the probability is (1/6)^5 power.<span />