Hey there,
Yes, that is a crucial step before communicating the answer. If you make a mistake in math and spot it, it will hardly influence your performance.
However, once the wrong number is communicated its harder to recover from.
There are two types of feasibility checks.
1. If you are quick enough, calculate twice. Some candidates have this ability and due to their speed, they can actually perform the calculations twice and still be within time limits.
2. If you are in the normal speed range like most of us, there are a few standard errors that can be prevented by the following measures:
- Check whether you have added 0s or lost them (using the scientific notation to calculate with large numbers helps a lot here)
- Moved punctuation somewhere along the way
- Do a quick % check if the number is in the right ballpark by comparing and relating to other numbers from the case math brief
- Check your units: did you calculate all numbers with their respective units and translated them correctly into a common uni?
- At the very least you should notice when a number is either way to big or way too small for the question asked (e.g., an ice cream parlor with 5bn yearly revenue should raise some eyebrows...)
Cheers,
Florian