What is the least common multiple of 8 and 14?

2 Answers
Mar 7, 2018

See explanation...

Explanation:

Alright, first we need to look at the what an LCM is. A least common multiple (LCM) is the lowest multiple that two or more numbers share.

For example, the numbers #2# and #8#, the LCM would be #8# based on the following set of multiples:

Multiples of #2:# 2, 4, 6, 8, 10, 12, 14,...
Multiples of #8:# 8, 16, 24, 32, 40, 48, 56,...

So lets look at the LCM of #8# and #14# now. How I like to do it is you multiply the smaller number by #2# until they are the same. They may seem confusing, let me explain.

Since #8# is the smaller of the two numbers, once we multiply that by #2# we get #16#. #16# is not equal to #14# so we keep going. To help you out, I've color coded the numbers so that #color(blue)(blue)# is a multiple of #color(blue)14# and #color(red)(red)# is a multiple of #color(red)8#

#14*2=28#
#color(blue)28!=color(red)16#

#8*3=24#
#color(red)24!=color(blue)28#

#8*4=32#
#color(red)32!=color(blue)28#

#14*3=42#
#color(blue)42!=color(red)32#

#8*5=40#
#color(red)40!=color(blue)42#

#8*6=48#
#color(red)48!=color(blue)42#

#14*4=56#
#color(blue)56!=color(red)48#

#8*7=56#
#color(red)56=color(blue)56#

Hope this helps!
~Chandler Dowd

Mar 7, 2018

56

Explanation:

To find the least common multiple find the prime factorization of each number and multiply the unique non repeated factors.

# 8 = 2 xx 2 xx 2 = 2^3# There are 3 factors of 2 in 8

# 14 = 2 xx 7 = 2^1 xx 7^1# There is 1 factor of 2 and 1 of 7 in 14

The 1 factor of 2 in 14 is a repeat of the 3 factors of 2 in 8. It is not
necessary to use that fourth factor of 2. three factors of 2 is enough

The 1 factor of 7 is a unique factor. The factor of 7 is necessary so

The LCM = # 2 xx 2 xx 2 xx 7 = 56#

The least Common Multiple of 8 and 14 is 56