I picked two smaller numbers to put on the number plates and showed her how to change the inequality sign with the simple explanation that you always want the sign to open to the bigger number. "Imagine that each number represents pieces of candy. Would you rather eat 2 pieces of candy or 7 pieces of candy?" Of course she changed it up a bit, "I think the inequality sign is a T-Rex and the numbers are long neck dinosaurs. The T-Rex will eat the bigger number." Fine.
We played out inequality game by changing the numbers and reading the inequality ("Nine is greater than one"). She really is one smart cookie :)