What is expanded notation?

Expanded notaion identifies each digit of a numeral (or just each nonzero digit) as a whole number and a power of ten (higher or lower than 1).

Example: 1234.5 is

(1 x 1000) + (2 x 100) + (3 x 10) + (4 x 1) + (5 x 0.1) *[or 5 x 1/10]

*The term "expanded notation" is sometimes applied to the less structured form,

omitting the separate significant values. For the number shown this would be:

1000 + 200 + 30 + 4 + 0.5