We need to find the lowest common multiple of 9 and 11.
First, lets make a list of multiples for each number.
for 9= 9,18,21,27,36,45,54,63.72,81,99
for 11= 11,22,33,44,55,66,77,88,99
Now, we need to find the common miltiple between both numbers.
In this case, the lowest common multiple is 99.