Answer:
20100
Step-by-step explanation:
There are 200 numbers in this addition problem. To add this, we can do 1 + 200, 2 + 199, 3 + 198 and so on. All of these pairs have a sum of 201 and since there are 200 / 2 = 100 pairs the answer is 201 * 100 = 20100.
