A
common denominator is a that is shared between two or more . Consider a few examples.
Pair of Fractions
|
Common Denominator
|
32 and 35
|
3
|
108 and 105
|
10
|
1711 and 176
|
17
|
Fractions can always be rewritten to all have a common denominator. This process requires writing by expanding or the fractions. As an example, take a look at a pair of fractions with different denominators.
31and21
These fractions are in their simplest form, which means that they can only be expanded. Write the of their denominators,
3 and
2, to find the of expansion.
Multiples of 3:Multiples of 2:3,6,9,12,15,18,…2,4,6,8,10,12,14,…
There are two potential common denominators in these lists. Expand the first fraction by
312=4 and the second fraction by
212=6 to make them have a common denominator of
12.
3×41×42×61×6=124=126
Now the fractions share a common denominator.
124and126