Binary Converter | Python Fiddle

import time

def playAgain():
    print('Do you want to convert another number?')
    return input().lower().startswith('y')

def showInstructions():
    print('''
Binary is amazing. It is a base 2 system.

2^0 = 1
2^1 = 2
2^2 = 4
2^3 = 8
2^4 = 16
2^5 = 32
2^6 = 64
2^7 = 128

76543210

Those are the 8 bits we are working with. Each will
be replaced with a 1 or a 0 depending on whether we
need its number to create the sum.

200 is our example.

200 = 128 + 64 + 8
1×2^7 + 1×2^6 + 0x2^5 + 0x2^4 + 1×2^3 + 0x2^2 + 0x2^1 + 0x2^0

So in binary, 200 is

11001000

Now you try another number and check your answer
with this program.''')
    input()
    print()

while True:
    print('Would you like to view the explanation?')
    if input().lower().startswith('y'):
        showInstructions()
    print('I can convert numbers to 8-bit binary code.')
    print('Enter a number less than or equal to 255.')
    theirNumber = input()

if theirNumber.isdigit():

if int(theirNumber) > 255:
            print('Please, enter a number less than or equal to 255.')
            theirNumber = input()

if int(theirNumber) >= 128:
            D7 = 1
            theirNumber = abs(int(theirNumber) - 128)
        else:
            D7 = 0

if int(theirNumber) >= 64:
            D6 = 1
            theirNumber = abs(int(theirNumber) - 64)
        else:
            D6 = 0

if int(theirNumber) >= 32:
            D5 = 1
            theirNumber = abs(int(theirNumber) - 32)
        else:
            D5 = 0

if int(theirNumber) >= 16:
            D4 = 1
            theirNumber = abs(int(theirNumber) - 16)
        else:
            D4 = 0

if int(theirNumber) >= 8:
            D3 = 1
            theirNumber = abs(int(theirNumber) - 8)
        else:
            D3 = 0

if int(theirNumber) >= 4:
            D2 = 1
            theirNumber = abs(int(theirNumber) - 4)
        else:
            D2 = 0

if int(theirNumber) >= 2:
            D1 = 1
            theirNumber = abs(int(theirNumber) - 2)
        else:
            D1 = 0

if int(theirNumber) >= 1:
            D0 = 1
            theirNumber = abs(int(theirNumber) - 1)
        else:
            D0 = 0
            
        print(str(D7) + str(D6) + str(D5) + str(D4) + str(D3) + str(D2) + str(D1) + str(D0))

else:
        print('That is not a number.')

if not playAgain():
        print('Ok, maybe another time. See you then!')
        time.sleep(5)
        break

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