Answer:
3985
Explanation:
Note: predecessor means a number before for example predecessor of 4 is 3. Similarly, successor is a number after for example the successor of 4 is 5.
The predecessor of the predecessor of 2987 = 2987-2 = 2985
Let 2985 be x
The greatest 3 digit number = 999
And the successor of the greatest 3 digits number would be = 999+1 = 1000
let 1000 be y
We have find the sum of x and y
= 2985+1000
= 3985