7. (2004 College Entrance Examination, Liaoning Province) A bag contains 10 identical balls, 5 of which are marked with the number 0, and 5 are marked with the number 1. If 5 balls are drawn from the bag, what is the probability that the sum of the numbers on the 5 balls drawn is less than 2 or greater than 3?
7. $\frac{13}{63}$ The probability of the sum of the digits being exactly 2 or 3 is $\frac{2 C_{5}^{2} C_{5}^{3}}{C_{1}^{5}}=\frac{50}{63}$, so $P=\frac{13}{63}$.