Question

Find the least common multiple (LCM) of 7 and 12.

Answer 1

Answer:

84

Step-by-step explanation:

Method 1 ; Prime factorization

$7 ,12\\\mathrm{Prime\:factorization\:of\:}7:\quad 7\\\mathrm{Prime\:factorization\:of\:}12:\quad 2\cdot \:2\cdot \:3\\= 847\times\:2\times\:2\times\:3\\= 84$

Method 2 ;Multipliers

$\mathrm{The\:multipliers\:of\:}7\\=7,\:14,\:21,\:28,\:35,\:42,\:49,\:56,\:63,\:70,\:77,\:84,\:91,\:98,\:105...\\\\\mathrm{The\:multipliers\:of\:}12\\=12,\:24,\:36,\:48,\:60,\:72,\:84,\:96,\:108,\:120,\:132,\:144,\:156,\:168,\:180...\\\\\mathrm{The\:smallest\:common\:number\:is} \\=84$

Method 3 ; Using GCD

$lcm\left(a,\:b\right)=\frac{|a\cdot b|}{gcd\left(a,\:b\right)}\\\\\mathrm{Greatest\:Common\:Divisor\:of\:}7,\:12:\quad 1\\=\frac{\left|7\times\:12\right|}{1}\\\\= 84$