# Assistance with += Operator in Python

Hi All,

Absolute n00b here so take it easy on me. I am making my way through the Data Science course, and gotten through to a section asking me to do a Medical Insurance Project.

I am trying to use the += operator, but it is not working as it should.

``````# create the initial variables below

age = 28

smoker = 0

bmi = 26.2

sex = 0

num_of_children = 3

# Add insurance estimate formula below

insurance_cost = 250 * age - 128 * sex + 370 * bmi + 425 + num_of_children + 24000 * smoker - 12500

Message1 = 'This persons insurance cost is '

Message2 = str(insurance_cost)

Message3 = ' dollars'

MessageComplete = Message1 + Message2 + Message3

print(MessageComplete)

# Age Factor

age += 4

new_insurance_cost = 250 * age - 128 * sex + 370 * bmi + 425 + num_of_children + 24000 * smoker - 12500

change_in_insurance_cost = insurance_cost - new_insurance_cost
``````

The New insurance Cost is meant to add the age by four, but the I get the same result despite using this operator.

Any idea why?

Seems to work fine? When I print the new and changed insurance cost I get the expected values:

``````change_in_insurance_cost = insurance_cost - new_insurance_cost
print(new_insurance_cost)
print(change_in_insurance_cost)
``````