A small piece of information for any potential applicants that may come along and see the maths problem posed in the original post. Problems such as this are part of the estimation section of the aptitude tests sat on the pilot additional testing day. The questions do not require an exact answer to be calculated.
You are presented with the question and a selection of multiple choice answers. Provided you can quickly estimate a ballpark number and magnitude for the answer, then the correct multiple choice answer is easily deduced. The true difficulty in this test is being able to do this estimation process repetitively, while under time pressure and after having already sat other aptitude tests.
This is going off of memory so don't hold me to the exact details. Answering all questions in the section requires an answer to be selected in around 10-15 seconds. I'm unsure if incorrect answers impact the final score, however I still elected to focus on accuracy over completing all questions and achieved a successful result regardless. The questions are composed of one or more maths operations applied to some combination of integers, fractions and/or decimals.