Answer:
21 is the l.c.m of 7 and 21
explanation:
[tex]\sf \bold \mathrm{The\:LCM\:of\:}a,\:b\mathrm{\:is\:the\:smallest\:positive\:number\:that\:is\:divisible\:by\:both\:}a\mathrm{\:and\:}b[/tex]
7 : 7
21 : 3 * 7
.
multiply, 7 * 3 = 21 - which is divisible by both 21 and 7
