What is a common denominator for 5/6 and 2/9?
2 Answers
18
Explanation:
We have
And now we gather up the largest groups of primes we can.
We have a group of 2s (just one of them, but that is a group), so we need a single 2.
We also have a group of 3s (there's two of them in the 9, so we need two 3s).
Therefore:
We can now convert the fractions:
Explanation:
To start with lets just think about the bottom numbers of 6 and 9.
Notice that 9 can be written as
So each 9 contains a 'spare' 3
Adding 9's means we accumulate the 'spare' 3's
Get 2 lots of 'spare' 3's and we have another 6. Which means we can exactly divide 6 into it with no remainder.
1st 9
2nd 9
Every time you get another 6 you have found a common multiple.
So 18 is the first common multiple of both 6 and 9