Answer: 200
Explanation: First start out with 20 even numbers:
2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40
As stated, you have to add the first ten together, and then add the last ten together
First ten:110 Last ten:310
Then subtract:
310-110=200
