When adding two numbers, such as 123 and 423, care is taken to first line them up and then add like digits. How does expanding t
his expression to [(1 × 102) + (2 × 101) + (3 × 100)] + [(4 × 102) + (2 × 101) + (3 × 100)] make the operation more like a polynomial addition problem?
Think of 10^2, 10^1, and 10^0 as x^2, x^1, and x^0. When you add polynomials, you can only combine like terms. When you add expanded numbers, you can only combine like powers of 10.
