L1 means taking one language, English or Higher Mother
Tongue.
R5 means taking 5 relative subjects, including at least 1 maths, 1
science and 1 humanities. so you can have 2maths 2science and 1
humanities or any other combination as long as u have one of each
kind.
L1B4 from what i know, is 1 language, EL or HMT, then ur 4 best
subjects.
correct me if im wrong...