Question

find the common factors of the following numbers.then find their HCF
1)20,45 2)16,56 3)36,60 4)42,70 5)30,50 6)40,60 7)72,48 8)25,90

Answer 1

Answer:

Using prime factors to find the HCF and LCM

Numbers can be broken down into prime factors using prime factor trees. ...

Find the HCF and LCM of 24 and 180.

Cross any numbers used so far off from the products.

To find the LCM, multiply the HCF by all the numbers in the products that have not yet been used.

www.bbc.co.uk › revision › 6

Answer 2

1) .20= 2....4....5...10...20

45= 3....5...9...15...45.....common factor are 5

5 20 45

4 9....hcf is 5

2) 16= 2.....4.....8.....16

56= 2....4....7....8....14....56.....common factors are 2...4 and 8

3) 36= 2....3...4....6...9...12...36

60= 2....4....5..6...10...12...15...20...30...60

common factors are 2...4...6...12..

4) 42= 2....3....6...7....42

70= 2....4...5..7...10...14...70

common factors are 2...7

5) 30= 2..3....5....6....10...30

50= 2...5....10...50

common factors are 2...5...10

6) 40=2....4....5...8...10...20...40

60= 2...3..4...5...6..10...12...15...20...

common factors are 2...4...5...10..20...

7) 72=2.....3...4...6...8....9....12..72

48=2....3...4...6...8....12...16...48..

common factors are 2...3....4...6...8...12...

8) 25=5....25

90=2....3...5...9..10...15..19...30..

common factors are 5.....only

Hope it helps you