Define a range, return all numbers of range that are NOT in csv data

[ichabod801]

That looks like the right direction, but note that you are double using n as a parameter to in_range and as a for loop variable on line 36. I would really suggest learning to use return values. Here's how I would have done it:

def in_range(n, num_range):
    return num_range['start'] <= number <= num_range['end']

def find_range(n):
    for num_range in _number_ranges:
        if in_range(n):
            break
    return num_range

def check_range():
    userinput = input("Enter the Number Yo")
    num_range = find_range(int(userinput))
    print('{} is a {} number'.format(userinput, num_range['name']