Identify the value of each digit in numbers given to three decimal places

What this means, in plain words

A decimal writes parts of a whole using the places after the point: tenths, then hundredths, then thousandths.

A digit is one of the ten symbols, 0 to 9, that all numbers are written with.

Number work here is about how our number system is built, and about knowing what a number is worth rather than just how it is spelled.