Hi, can you help me with understanding the wording?

So if the d with the square around it, is the decimal expression for rounding to the nearest thousandth, that is the number 8. Correct?

And the number of decimal places where d with the square and d differ: what does it mean? Does it mean the difference between 5 (as d has 5 numbers after the decimal point) and 3 (as rounding to the nearest thousandth would mean 3 numbers after the decimal point)?

thanks