stupidly easy hw that I need help with

[icantcodeforcrap]

I have to do a stupid tip calculator hw assignment for my beginning coding class. It's literally only our second assignment, but I'm stuck. For some reason, the program will not calculate the tip. I don't know what I'm doing wrong. It's probably something basic. Here's the input and output.

Input-----------------------------

tax = .06

# How much is the bill?
bill = input("How much is the bill? ")

# What percentage of the tip would you like to enter?
tippy = input("What percentage of the tip would you like to enter? ")

# Tip added
print "Tip added is " + str(tippy)

# What is the total bill?
TotalBill = (bill * tax) + (bill * tippy) + bill
print "Your total bill is " + str(TotalBill)

Output---------------------------

Output:
How much is the bill? 100
What percentage of the tip would you like to enter? 10
Tip added is 0
Your total bill is 106.0

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Oh that's fancy. Sorry, literally just found this site, don't know much about it