## Using Functions

There are two important things to remember when using functions with arguments. The first thing is that the order matters. For example, the `random.randint()` function takes in two arguments. The first is the minimum value, and the second is the maximum value. If you put them in correctly, you get a random number:
```import random
number = random.randint(1, 10)
print(number)
# random number between 1 and 10
```
But if you reverse the order and try to put the larger number first, you will get an error:
```import random
number = random.randint(10, 1)
print(number)

# Traceback (most recent call last):
#   File "main.py", line 2, in <module>
#     number = random.randint(10, 1)
#   File "random.py", line 370, in randint
#     return self.randrange(a, b+1)
#   File "random.py", line 353, in randrange
#     raise ValueError("empty range for randrange() (%d, %d, %d)" % (istart, istop, width))
# ValueError: empty range for randrange() (10, 2, -8)
```
The second thing is that the data type matters in many cases. The `random.randint()` function works fine with integers, but if you try to use floats or strings, you will get an error:
```import random
number = random.randint(1.5, 10.6)
print(number)

# Traceback (most recent call last):
#   File "main.py", line 2, in <module>
#     number = random.randint(1.5, 10.6)
#   File "random.py", line 370, in randint
#     return self.randrange(a, b+1)
#   File "random.py", line 309, in randrange
#     raise ValueError("non-integer arg 1 for randrange()")
# ValueError: non-integer arg 1 for randrange()
```

### Exercise 1 of 5

Call the function with the correct argument.
```# name must be a string
def say_hello(name):
print("Hello " + name)
```

### Exercise 2 of 5

Call the function with two numbers as arguments.
```def add_numbers(a, b):
print(a + b)
```

### Exercise 3 of 5

Call the function with the correct arguments so the function prints True.
```def is_less_than(a, b):
print(a - b < 0)
```

### Exercise 4 of 5

Call the function with the correct arguments.
```def describe_person(name, age):
future_age = str(age + 4)
print("In four years, " + name + " will be " + future_age + " years old")
```

```def get_time_period(hour):