>>1036866 (OP)
What exercises? There are exercises that will causes masters to struggle, those are called 'research topics.' Learning mathematics is always going to be a struggle, as the exercises should just be every so slightly harder than comfortable, that's where you learn. It's true, you probably won't need to write your own algorithm to compute the SVD of a matrix, but could you? The correct application of mathematics is usually the hard part. For example, if I ask you to compute the optimal trajectory to land on mars, the fact that you have a computer which can solve many simultaneous differential equations is the least of your worries, the real difficulty is in writing the equations to solve in the first place.
Of course, there's still plenty of areas in which the known algorithms could do with significant improvements, in those areas, you'll be writing your own implementations for everyone else to use, and "Numerical Methods" is a blend between ComSci and Mathematics.
If you just want to make shitty web pages, you probably don't need anything more than highschool.