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2 HCF/LCM and Prime Factor (1/3) x xx x xx Prime Factors 12 = 2 x 2 x 3 Prime Factors 18 = 2 x 3 x 3 Circle the common factors HCF = 2 x 3 = Find the HCF of 12 and 18. LCM = HCF x 2 x 3 Underline the remaining numbers = 6 x 2 x 3 = 36 End of Slide

3 HCF/LCM and Prime Factor (2/3) x xx x xx Prime Factors 27 = 3 x 3 x 3 Prime Factors 45 = 3 x 3 x 5 Circle the common factors HCF = 3 x 3 = Find the HCF of 27 and 45. LCM = HCF x 3 x 5 Underline the remaining numbers = 9 x 3 x 5 = 135 End of Slide

4 HCF and LCM (3/3)Exercises Use Prime Factor Trees to find the HCF and LCM of: a) 24 and 36 b) 36 and 54 c) 24 and 56 d) 54 and 56 e) 60 and 36 f) 15 and 40 End of Slide