Answer:
The sum given is not reasonable.
Explanation:
Given : Jill added 450+790+123 and 1163.
To find : Is this sum reasonable? Explain.
Solution :
To find the correct result we have to add them step by step,
4 5 0
7 9 0
+1 2 3
-----------
13 6 3
So,

The sum given is not reasonable.
Therefore, The given sum is not correct.