---
id: practical-python-1.9
source_exercise_id: "1.9"
title: "Making an Extra Payment Calculator"
section: "1.3 Numbers"
source_path: "01_Introduction/03_Numbers.md"
source_repo: "https://github.com/dabeaz-course/practical-python"
source_commit: "93dca856b41c61a0a0f85ae334116e4c125629ea"
student_visible_solution: false
has_private_solution: false
skip: false
---

# Exercise 1.9: Making an Extra Payment Calculator

> Source: Practical Python Programming, `01_Introduction/03_Numbers.md`.

### Exercise 1.9: Making an Extra Payment Calculator

Modify the program so that extra payment information can be more generally handled.
Make it so that the user can set these variables:

```python
extra_payment_start_month = 61
extra_payment_end_month = 108
extra_payment = 1000
```

Make the program look at these variables and calculate the total paid appropriately.

How much will Dave pay if he pays an extra $1000/month for 4 years starting after the first
five years have already been paid?

## 关联来源

- [[summaries/03_Numbers]]