Ok, so 2/5 tiles are green and 2/10 are yellow.
So first we have to make them have the same denominator (bottom number) so we can compare them. To do that we have to find a number we can times the green tiles bottom number by to make it match the bottom number of the yellow tiles. Then, we times the top number (or numerator) of the green tiles to match, so we can accurately compare the two. Like this...
2 2 So, we need a number to times the 5 by to make it match the 10.
---- = ----
5 10
5 x 2 = 10 If we times 5 by 2, we get 10!
Now, all we have to do is times the top number by 2 as well.
2 x 2 = 4 Now that the two numbers have the same denominator, we can
---- accurately compare the two!
5 x 2 = 10
4 2
---- green tiles vs. ---- yellow tiles
10 10
and now we can see that their are more green tiles than yellow (by 2) I hope this helps you, Cheers!