For several weeks David worked on a drawing of his superhero bus. He used a green water color pencil for the grass and trees. Since the drawing was quite intricate, he left it and returned to it many times. One morning, David needed to finish coloring the grass and trees so he went to look for the same green pencil he had been using. He encountered a problem; there were four green pencils of varying shades in the container.
Which one was the one he'd used the day before?
He looked at the numbers at the top of the pencils. He tried to compare the shades but that still didn't help since they were so close. He went to the table and placed each of the pencils next to the colored grass. He still was undecided so he engaged the help of his friend Emily.
She pulled a pencil from his hand and said,
"I think its this one. All you have to do is color beside the same spot and you can see if it matches!"
David's superhero bus is complete.