Binary numbers are just "base 2" numbers. They work the same way as "normal" base 10 numbers, but with two symbols instead of ten.
0 and 10, 1, 2, 3, 4, 5, 6, 7, 8, 9
Each 1 in a binary number represents an ever-greater multiple of 2. In a 4-digit number, that means you have the eights place, the fours place, the twos place, and the ones place. Similar to how in decimal you would have the thousands place, the hundreds place, the tens place, and the ones place.
Click to play video
You can write an integer in Python using binary syntax using the 0b prefix:
print(0b0001)
# Prints 1
print(0b0101)
# Prints 5
Leading 0s are often added for visual consistency but do not change the value of a binary number.