In our number system, each digit in a number represents a different power of 10. When a number is written in expanded form with base 10 notation, each digit is multiplied by the appropriate power of 10 and then added together. This representation accurately reflects the value of each digit in the number and allows us to easily understand and manipulate numbers. Therefore, numbers in expanded form with base 10 notation are equal to the number itself because they accurately represent the value of the number based on this system of powers of 10.
