How about this one:

Which is greater: 3/8 or  7/8?

Let's think of a pizza again - mostly, because I like pizza. Ok, back to the math.

The denominators are both 8, so let's look at a pizza cut into 8 pieces:

You're SUPER hungry... Do you want 3 pieces? Or 7 pieces?

7 is WAY more!

So 3/8 is less than 7/8

Sometimes, you can tell just by using your head!

Which is greater: 2/9 or 8/7 ?

Hmm... 2/9 isn't very much pizza - only 2 pieces out of 9... 

But, 8/7 is MORE THAN a whole pizza. Isn't it? In fact, it's 1 1/7.

A whole pizza AND another slice.

So 2/9 is less then 8/7