No.
1000000000 or, if negative numbers are permitted, then -9999999999
what this case number mean 9999999999
1000000000, 1000000001, 1000000002, ..., 9999999998, 9999999999
10,000,000,000
9999999999
9999999999 100000000
9999999999
No. When adding the smallest 2 digit number (= 10) to the smallest 2 digit number (again, 10) the result is a 2 digit number (10 + 10 = 20). When adding the largest 2 digit number (= 99) to the largest 2 digit number (again, 99) the result is a 3 digit number (99 + 99 = 198). As you can see, you'll either get a 2 or 3 digit number, but never a 4 digit number.
2 digit number
9999999999
999 + 9999999999 + 9999999999 + 8888888 = 20,008,889,885
0