In 42, the value of 4 is 4 hundreds, the value of 2 is 2 tens, and the value of 1 is 1 ones.
421 = CDXXI
by adding or subtracting the values of the digits in the front place
With 6 binary digits, you have 26 different possibilities. This is because there are two possibilities for each digit, and each digit is independent of the other digits - so you just multiply the possibilities for each digit together.
That is the special purpose of the zero didit in numbers, such as 1005.
123,456,789 and 113,355,779
Mutilply the values of the digits.
The different digits have different values.
Individual digits within a number have place values, not whole numbers.
Three significant digits.
The factors of 421 are: 1, 421
64 or 123
They are called the digital roots.
The two sets of digits have different place values.
Zero or five.