Universal Abacus (Combo Pack of 2) Level:-1 (Book- A_B Both) Abacus is a great way to teach numbers and arithmetic to kids. There are many ways to teach numbers to kids. Abacus is a great tool to teach your child simple math such as counting, addition, subtraction, multiplication and even division. This bundle of combo pack Contains 2 text books of levels 1 (A and B both). It helps in whole brain development of a child. Both books are very attractive and of very good quality.