Economics has an incredible amount of mathematics. In fact, you wouldn't be too far off the mark if you were to rename it as Applied Mathematics (economy). Take the following model below, from my school notes, which describe how firms collude to set high prices.
Because of this, LSE economics students undergo a gruelling one-month math course before the start of their Masters programme. At the end of it, they take mathematics exams. It is hardly any fun, but does it really help with economics?