Can you imagine the square on the back? Where will its $1$ be? Where will its $10$ be?
So what will be on the back of the $20$ in the $100$ square in the picture? The $30$? Does this help with the $100$?
You could print off the $100$ square, or draw your own, and write just, for example, $1-10$ on the back of it to get you started. Can you see where $11-20$ would be? Perhaps this helps to predict the other numbers.