tick method

No he can't - you can always do it either way :-) (Be aware what ticks are just in case he asks you to explain what they are in a written part of a question, but I will be surprised if he ever does.)

Which bit do you want me to elaborate? You do not need to use ticks in calculation questions. I doubt he will ask you ever to explain, but I explain all about ticks in my free lectures (and I am not going to type out the lectures here :-) ) One tick is the smallest movement, which is 0.0001 in the case of exchange rate instruments, and 0.01 in the case of interest rate instruments.

Great :-)