Other than the CFA Institute official study material, there are online resources which can be used to clear concepts, even for non CFA aspirants.
Check out formulas, examples, questions, study material resources online here.
Annuity Example Question | CFA Level 1 - Analystprep
Check out calculators use for annuity due calculations
(BGN) Annuity Due Calculations Using BA II Plus
Some multiple choice questions examples
Chapter 3 Multiple-Choice Quiz
Free CFA Level 1 Flashcards | Kaplan Schweser
More inputs on Business math
11.3: Present Value of Annuities – Business Math: A Step-by-Step Handbook Abridged