The expanded form of the number 557251 using multiplication with powers of 10 (which can be represented with the "x" sign) is:

$557251 = (5 \times 100000) + (5 \times 10000) + (7 \times 1000) + (2 \times 100) + (5 \times 10) + (1 \times 1)$

In terms of powers of 10:

$557251 = (5 \times 10^5) + (5 \times 10^4) + (7 \times 10^3) + (2 \times 10^2) + (5 \times 10^1) + (1 \times 10^0)$

This breaks the number down into its individual place values.

Do you want any further details or have questions?

Here are 5 related questions to expand this:

1. How do you convert numbers into scientific notation?
2. What is the expanded form of a decimal number like 234.56?
3. Can you explain how to find the place value of each digit in a number?
4. How would you express a number like 780930 in expanded form?
5. How is the concept of expanded form used in algebraic expressions?

Tip: When expanding numbers, always start from the left-most digit, which has the highest place value, and move right!