7 resources.
Quick tests to check whether a number is divisible by 2 through 12, with worked examples.
A quick-reference table of squares from 1 to 30 and cubes from 1 to 20.
Finding HCF using Euclid's division algorithm and prime factorization, plus verifying LCM x HCF = product of two numbers, with worked examples.
Proving a number is irrational by contradiction, and telling whether a fraction has a terminating or repeating decimal expansion, with worked examples.
The formula for counting how many divisors a number has from its prime factorization, with worked examples.
What Euler's number, the imaginary unit, Pythagoras' constant, and pi actually represent, including the repeating cycle of powers of i, with a worked example.
What a prime number is, why 0 and 1 are neither prime nor composite, and what twin primes are, with a worked example checking a number for primality.