Unit 8 Lesson 4: Exercise 3

Using any of the methods learnt in the examples, find the H.C.F. of these sets of numbers. 

1. 15, 18 and 21
2. 28, 32 and 20
3. 36, 54 and 60
4. 16, 24 and 32
5. 21, 63 and 84
6. 36, 45 and 90
7. 50, 75 and 100
8. 34, 40 and 56
9. 28, 42 and 70
10. 72, 108 and 162