A decimal number is written in expanded form by multiplying each individual number by the value of the decimal place that it occupies. Expanded form is rarely used, as both decimal form and mixed form are more convenient and practical forms of a non-whole number.
For example, the number 57.5 written in expanded form would be equal to (5 * 10) + (7 * 1) + (5 * 0.1). Each number is multiplied by its location value. The 7 is in the one's column, so it is represented by 7 * 1 in a bracket. If all of the individual brackets in the expanded form are evaluated and the results are added, the original number in decimal notation will be obtained.