Highest Common Factor (HCF) from prime factorisation

Find the highest common factor (HCF) worksheet of 2 numbers by first finding the prime factorisation of the two numbers.

Range of numbers

Numbers from 10 to 30
Numbers from 10 to 50
Numbers from 10 to 100
Numbers from 50 to 100
Numbers from 50 to 200

Number of problems

3 problems (enough space on the worksheet to do it there)
10 problems (working out will have to be done elsewhere)

Answer sheet

Include answer sheet.