3
2 and 15 3 and 10 5 and 6
hcf(10, 21) = 1 ⇒ 10 & 21 relatively prime hcf(12, 54) = 6 ⇒ 12 & 54 not relatively prime hcf(15, 27) = 3 ⇒ 15 & 27 not relatively prime hcf(21, 38) = 1 ⇒ 21 & 38 relatively prime
3
Any two numbers that have a common factor greater than 1 will have a LCM less than their product, eg: LCM(10, 15) = 30 < 10 x 15 = 150 (since HCF(10, 15) = 5) LCM(6, 10) = 30 < 6 x 10 = 60 (since HCF(6, 10) = 2) LCM(18, 27) = 54 < 18 x 27 = 486 (since HCF(18, 27) = 9)
10
6 and 10 2x3=6 2x5=10 HCF=2 LCM=30
The HCF is 3
The GCF is 5.
The GCF is 5.
10.
The GCF is 2.