In a three-digit number the digits go in columns.
Hundreds | Tens | Ones |
Look at the number:
345
Put each digit in the columns like this:
Hundreds | Tens | Ones |
3 | 4 | 5 |
So 345 is three hundred, four tens and five ones, which is three hundred and forty-five.
And 504 is five hundred, no tens and four ones, which is five hundred and four.
Hundreds | Tens | Ones |
5 | 0 | 4 |