The `int()` function can be useful if you're working with data. For instance, imagine that we have a lot of numbers that need to be modified, but **all of them have a string data type**. This code leads to an error:


```
Input:
value = "123"
new_value = "123"+10

Output:
TypeError: can only concatenate str (not "int") to str
 ```


Here, Python tries to concatenate the strings, but indeed its functionality doesn't allow it to do so, since 10 is related to the integer data type (**concatenation can be applied only to strings**).

Numeric data types are crucial in Python, so it is important to start with them. Here you will work with simple math operations and find out the purposes of learning different types of numerical data.

The main goal of this section is to clarify the boolean data types; it's a sub type of numeric data, but indeed it is more challenging. Since it is always better to excel in the more difficult topics, this section is a valuable part of your curriculum.

Strings are a way for us to implement your phrases in Python, that is, to give instructions to users who are the target audience of your program. Indeed, it is always better to be able to work with strings because they should be used in your code. You'll understand why soon.

This chapter consists of practical tasks that combine all the examined topics together with a bit of theory.