How do you find the HCF of 110 and 132

Draw a diagram breaking down 110 and 132 into their multiples (on whiteboard), e.g. 110=1110 132=1112 Circle the prime numbers, 11, and then break down the composite numbers (those that aren't prime) into their factors and circle the prime numbers each time, until only prime numbers are left. Multiply each common prime number in the lists, crossing off the numbers on each list when they have been used, to find the HCF So, HCF = 11*2=22.