100
thousands
55
38.5
The sum of the first 100 odd numbers (1 through 199) is 10000 (ten thou)
38.5
The average of the first ten prime numbers is 12.9.
2520 is the smallest multiple of of first ten natural numbers.
Just add them together, and divide the result by 10. (For the average of a larger set of consecutive odd numbers, it's faster to use the formula for an arithmetic series to add them up. Also, the average of such a set is the same as if you just average the first and the last number.)
Add them up and divide that total by ten. 4, 6, 8, 9, 10, 12, 14, 15, 16, 18
3.141592653
Ordinary numbers
The first ten positive numbers total 55.
The first ten happy numbers are: 1, 7, 10, 13, 19, 23, 28, 31, 32, 44
16,17,18,19,20,21,22,23,24,25.
100
thousands