
Multiples, Multiples, Multiples
Keep in mind that mathematicians are a literal bunch.
So if you come across a concept called multiples, you
can guess that multiplication is going to play a big part in it.
The multiples of an integer are the product of that integer
and another integer. Consider the number 7. Some multiples of 7
are:
If you have two different numbers, you may be asked to
find the least common multiple (LCM) the two numbers
share. The LCM of two numbers is defined as the smallest integer
that is a multiple of both numbers. Sometimes the LCM is simply
the two numbers multiplied together. The LCM of 7 and 5 is 35, for
instance. This is because 7 and 5 are both prime numbers. However,
the LCM of 12 and 10 is not 120. To find the LCM of these two numbers,
we have to run some numbers through the factor machine:
Multiples of 10  Multiples of 12 

10  12 
20  24 
30  36 
40  48 
50  60 
60  72 
70  84 
80  96 
90  108 
100  120 
110  
120 
Can you see a number less than 120 that both numbers have
in common? If you don’t, you must have some vision problem that
makes the number 60 invisible to you. 60 is the LCM of 10 and 12.
There’s a complicated mathematical method to determine
LCM, and there’s the way shown above. On the SAT, take the easy
route.
