A penny graph is a way to visualize and keep track of how many pennies you have. It's like a chart with boxes that you fill in for each penny you get or spend.
Let's say you start with no pennies in your piggy bank. You draw a line on a piece of paper and write "0" at the bottom. This is the bottom of your penny graph.
When you find a penny on the ground or get one as change, you draw a little circle or dot above the line and write "1" next to it. This means you now have one penny.
If you get another penny, you draw another circle or dot above the first one and write "2" next to it. And so on, for every penny you get.
If you spend a penny, you draw a line through the circle or dot and write "spent" next to it. This shows that you no longer have that penny.
You can keep going with your penny graph as long as you want, adding circles and dots for every penny you get or spend. It can be a fun way to keep track of your money and see how it adds up over time.