Which is the correct way to write 507,021 in expanded form

Hello Eriseldasamayoa, the correct way to write 507,021 in expanded form is,

Standard Form:

507,021.

Expanded forms can be written like a sentence or stacked for readability as they are here.

Expanded Notation Form:

500,000 + 0 + 7,000 + 0 + 20 + 1.

Expanded Factors Form:

5 * 100,000 + 0 * 10,000 + 7 * 1,000 + 0 * 100 + 2 * 10 + 1 * 1.

Expanded Exponential Form:

5 * 105 + 0 * 104 + 7 * 103 + 0 * 102 + 2 * 101 + 1 * 100.

Word Form:

Five hundred seven thousand, twenty-one.