Why can we see the moon in the daytime?

Rey asked me this question when we were out cycling. "Why do we see the moon in the day and sometimes we can't?"

Ok, somewhere in my mind, I know the answer to this. But I have to find the simplest, most explainable answer that a 5 year-old boy can understand. I decided to draw the Sun, moon and Earth diagram and teach him all about the rotation of the Earth and the Moon. Maybe you can find the answer on Rey's blog. That, I think will take him hours to type it in.

This is a funny answer I found on the net.

Q: Why is it that we can see the moon in the day?

A: The moon must report to the sun 12 times per year to keep it advised of sinister goings-on on the dark side of the Earth.