Draw a table with 15 columns on the board or modelling book. Write “Ones” in the middle column, then, going to the left, “Tens”, “Hundreds” up to “Ten-millions”. To the right of the Ones column discuss why the next heading is “Tenths”, noting the “mirroring” of the column names is about the Ones column, Hundredths, Thousands map onto Thousandths, and so on, up to Ten-million mapping onto Ten-millionths. Enter a number like 456.897603 in the table and get the students to read it as 456 plus eight tenths plus nine hundredths plus seven thousandths ... down to three millionths.

Repeat for other numbers.