When we write number words in numerals we look at the hundreds, tens and ones.
Let's look at three hundred and forty-five.
This is three hundred, forty and five.
345 = 300 + 40 + 5
Or three hundreds, four tens and five ones.
In a three-digit number, the digits go in columns like this:
Three hundred and forty-five is written as 345.
Are you happy with that?