What is the 6th term in this sequence? 1, 4, 9, 16...

What is 1 + 2 + 3 + ... + 98 + 99 + 100?

Benny has purchased 10 books. The 1st book cost $1, the 2nd, $2, the 3rd, $4, and the 4th ,$8, and so on. How much did Benny pay for the 10 books?

What is the 8th term in this sequence? 3, 4, 6, 9...

What is 1 + 3 + 5 + ... + 95 + 97 + 99?