急求数学题（英）primefactorizationmethod←特别是这句Ineachofthefollowing,findtheH.C.F.andL.C.M.byprimefactorizationmethod.(a)12,18(b)16,20,24

Question

急求数学题（英）
prime factorization method←特别是这句
In each of the following,find theH.C.F.and L.C.M.by prime factorization method.
(a)12,18
(b)16,20,24

Answer 1

HCF: 最大公约数
LCM：最小公倍数
prime factorization method: 素因子方法
(a) 12 = 3*2*2; 18 = 3*3*2, so
HCF = (3*2) = 6; LCM = 2*2*3*3 = 36 (最多2个2,2个3）
(b) 16 = 2*2*2*2, 20 = 2*2*5, 24 = 2*2*2*3,so
HCF = (2*2) = 4; LCM = 2*2*2*2*5*3 = 240 （最多4个2,1个5,1个3）