Mathematics for IGCSE & O level - Using A Calculator (Section 1 - No. 1)
What should you do if the answer is not clear to the estimated answer?
This suggests that you have used the correct order of operations.
This suggests that you have not used the correct order of operations.
Ignore it.
Round down.
Paliwanag
The answer being so far from your estimation suggests that you have not used the correct order of operations.