Are you sure this is your junior high school topic? As far as I know, this is arithmetic progression from the first grade. The solution is as follows

Question 1: The tolerance is 99. Number of items calculated: (9901-199)/99 = 98,98+1= 99. If * * *, there are 99 numbers, and there is a minimum value plus a maximum value. Multiply the number of terms and divide by 2 to get (199.

Question 2: Look at the law of the formula and change the formula to: 1 and1/2-(3-1/6)+(3+112)-(5-1). The formula1+1/2+1/6+112+1/20+1/30+1.

After graduating from college, I almost forgot everything about high school. This is my method, and there may be a shorter answer.