Math HL: Tricky problems. Getting the content down is easy, but applying it to the problems can be tough. Practice, practice, practice. Physics HL: Tricky concepts. The problems seem pretty tough, but if you get your head around the concepts (not just the math), you can solve them. International Baccalaureate (IB) Mathematics Higher Level (Math HL) students must thoroughly study algebra, calculus, functions and equations, circular functions and trigonometry, matrices, vectors, statistics, and probability. Top 5 Most Difficult IB Subjects 1. Further Maths HL. The Further Maths HL course in IB is easily one of the hardest subjects to nail from the lot. 2. Maths HL. Taking the position right after its big brother, Further Maths HL, Maths HL is one of the hardest IB 3. Chemistry HL. Chemistry HL is Subjectively, I believe AI HL is harder than A level math mainly because there's some further math topics such as matrices or coupled differential equations that might be hard to apply knowledge for real life situations. Also, it's harder because the course is so queer. I think the difficulty of the course comes from the sheer amount of content and the questions that come in the exams. I don't find any of the concepts particularly difficult or confusing, however, I really struggle with difficult exam style questions where their application comes into place. ailY5.