Answer:
The answer to your problem is, 2020
Explanation:
First lets break down the problem:
One way that I do it is by breaking the biggest number in HALF
1000 | 1000.
Then adding what is supposed to be added in this case 20, to one of the halfs, which is 1000
20 + 1000=
1020, then adding the other half:
1020 + 1000 =
2020.
Thus the answer to your problem is, 2020