1/3 x 1/9
Change the denominator(bottom half) so that they have the same factors, but when doing this you have to change the top too. 3 x 3 is 9 so the denominator will be 9 for both fractions, then 1 x 3 is 3 so the equation will look like this:
3/9 x 1/9
Then you can multiply
3/9 x 1/9 = 3/9 which can reduce to 1/3
Hope this helps, it's harder to explain math virtually.