Factorised form and its uses
Revision Notes 1. The factorised form Factorisation is writing the number as a product of prime numbers. All like primes are collected together and written in the index form. Thus, the factorised form is: n = p1a × p2b × p3c × …… Where each of p1, p2, p3 , …. are distinct prime numbers […]
Cyclicality of unit digit of a^n
Revision Notes 1. What determines the unit digit of an? Unit digit of any an depends on just the ‘unit digit of a’ (and the rest of the digits of a can be safely ignored) and on n. As n assumes values 1, 2, 3, 4, ……. , the unit digit of an follows a cycle of […]
Divisibility Rules
Revision Notes 1. Divisibility by 2n i.e. by 2, 4, 8, 16, …. When a given number is divided by 2n, the remainder will be same as the remainder when just the last n digits is divided by 2n. If the last n digits, when divided by 2n leaves a remainder of 0 i.e. is completely divisible, then […]