Yadira's mom is buying hot dogs and hot dog buns for the family barbeque. hot dogs come in packs of 12 and hot dog buns in packs of 9. the store does not sell parts of a pack and yadira's mom wants the same amount of hot dogs as hot dog buns. what is the smallest total number of hot dogs that yadira's mom can purchase?

Ah hah !  People on are always asking us where they can
use this stuff in real life.  HERE is a perfect example of where
you can use Least Common Multiple in real life . . . when you're
buying hot dogs and buns !

When they come in packs, with different numbers in each pack
but you want to wind up with the same number of each item,
the number of each item that you should buy is the LCM of
the numbers in each pack. 

Yadira's mom absolutely aced her math in Middle School, so she
knows right away that the LCM of  9  and  12  is  36 .  This tells her
that she should buy  36 hot dogs (3 packs) and 36 buns (4 packs).