## Type Conversion

Let's say you have a string "145", and you try to do some math with it. You will get an error:
```var = "145"
result = var + 4
print(result)

# Traceback (most recent call last):
#   File "main.py", line 2, in <module>
#     result = var + 4
# TypeError: can only concatenate str (not "int") to str
```
To make this work, first convert "145" to an integer. The are several functions for converting types:
• `str()` - converts to string
• `int()` - converts to integer
• `float()` - converts to float
Let's retry the example above, but this time using the `int()` function:
```var = int("145")
result = var + 4
print(result)
# 149
```
This is especially useful for converting user input from strings to numbers:
```radius = float(input("Enter a radius: "))
area = 3.14 * radius ** 2
```

### Exercise 1 of 6

Write a line of code to convert a variable x to a string.

### Exercise 2 of 6

Write a line of code to convert a variable x to an integer.

### Exercise 3 of 6

Write a line of code to convert a variable x to a float.

### Exercise 4 of 6

Fix the error in the code.
```width = 15
length = input("Enter the length: ")
area = length * width
print(f"The area is {area}.")
```

### Exercise 5 of 6

Fix the error in the code.
```age = input("How old are you? ")
future_age = age + 20
print(f"In 20 years, you will be {future_age} years old.")
```

```result = "21" / 7