There is hardly much Math in Part C (Open Book)-perhaps, 1 or 2 questions max...and very basic arithmetic.
I'd say about 10% of the questions in Parts A (Fundamentals) and B(Practical) involve some Math. Most of the Math you'd have covered in the WIT-T, CM, and Practical seminar.
If you review the CWI body of knowledge, it'll give you an idea of the sort of questions that entail some Math.
If you can compute the C.E. of low alloy steel with the formula provided, then, you should have no problems with the level of difficulty of Math. From what I hear, it is no harder than NICET type Math.
Math questions should be the least of your concerns; and I would not be surprised if you got all correct.