Once upon a time, there was a big round ball. It was very thick and strong. The ball liked to roll around and play with its friends in the park.
One day, the ball met a new friend. The friend was a long and thin ruler. The ruler could measure things. The ball wanted to learn how to measure too.
The ruler taught the ball to measure. They measured a lot of things together. They measured a big tree, a small rock, and even a thick book. The ball was very happy to learn something new. The ball and the ruler became best friends and played together every day.
