I made a gst calculator and i need help on how can i make my code the way that it don't have to be dependent on the hard coding

Question

#GST Calculator
ammount = int(input("ammount: "))
def cal(a):
user = int(input("Tax: "))
if user == 18:
print(a * 1.18)
elif user == 12:
print(a * 1.12)
else:
print("Choose")
cal(ammount)

Answer 1

Use a variable which is modified by their input. something like this, I was thinking:

print(a * float("1.%s" % user))

Which will place the user number as the decimal for 1; which seems to be what you want to do.

That way you can avoid infinite if statements for every possible number.