when they ask you to do that, you show the value of each of its digits. You separate them depending on the order of the digits of the numbers and its clasification. For example if you were to exapnd the number 23 you may expanded as 20 and 3 to shoe the value of every digit. In this case the number expanded will be 2.000.000 + 10.000 + 5.000 + 400 + 70 + 3