Make a notebook in Sage Math Cloud and explain and perform a simple estimation. Include cells with Markdown for your text and explanation as well as cells with Python showing simple calculations.
If you want to learn more about Markdown and Python, here are some links to get started.
Explain what you are trying to estimate in words.
# This is a code cell, use it like a TI-84
1 + 2
If we are hungry each person will eat 3/8 of a pizza. X represents our class size.
http://gawker.com/how-many-pizzas-should-you-order-the-pizza-equation-wi-1697815579
x = 19
x * (3/8)
We need at least 7 pizza's if our assumption that each person will eat 3/8ths of a pizza is true.
But what if people aren't hungry and only eat 2/9 of each pizza? then we would need:
x * (2/9)
We would only need 4 to 5 pizzas. From this, I conclude, We need to determine a hunger scale before ordering any pizza.