I have to write a math/story book for a first grader. Any suggestions?

Question

In my 9th grade accelerated geometry class we have to write a book for a first grader that pertains to math.

He likes:

Pizza

Dr. Pepper

the color Red

Monster Trucks/dirt bikes/Nascar

his favorite animal is a Daschound

Answer 1

Combine the pizza and the Dachshund.  Have the dog eat parts of the pizza and use that to talk about shapes (circles and possibly triangles)  simple fractions - missing slices.  Good luck.  

Answer 2

Explain everything in shapes.

The red pizza sause oosed out of the round pizza,,, etc.