Answer: sum = 1200.
Step-by-step explanation:
Since we have two digits are numbers are given ,
So the only possible rounding or estimation will be done nearest to ones .
Rounding integers to nearest ones ,
\(87\text{ changes to }90\\34\text{ changes to }30\\\)
So,
Sum is given by
\(90+30=1200\)
So, our sum will be 1200.