Explanation: Place values of a number is defined as the position of digits in a number.
In the given number 7854.209, there are seven digits present.
The place of digit 7 will be thousands.
The place of digit 8 will be hundreds.
The place of digit 5 will be tens.
The place of digit 4 will be ones.
The place of digit 2 will be tenths.
The place of digit 0 will be hundredths.
The place of digit 9 will be thousandths.