If you were asked to divide 1,385.2 by 4 and add the result to the original number, then most people could do it in their heads.
Exactly the question asked. 1/8th is 12.5%
Simply 10% of 13,852 + 1/4 of that added on.
It's not a maths problem but to see if you have the ability to simplify thought processes as your brain bucket fills up.