A fun way to teach the little kids which number is bigger, is using some counting props and a chalkboard instead of a paper.
We chose to write some smaller numbers on chalkboard and demonstrate how the signs work.
In order for the kids to make the connection between the two amounts, you can use some counting props that you have at your house (we have counting teddy bears). After they build their numbers with the props, they will easily see what the difference between those two amounts is.
As for the signs, you can say that the shark is going to eat the bigger amount (therefor the bigger number) and that is why the wider side is pointing towards the higher amount... the shark is trying to get it! We hope this helped :-)