What is the expanded form of 430,290,100

So,

When you write a number in expanded form, you separate each non-zero digit and write it according to its place value.

430,290,100

400,000,000

30,000,000

We don't put anything for the millions place because there are none.

200,000

90,000

100

Then we join each of them with a plus sign.

400,000,000 + 30,000,000 + 200,000 + 90,000 + 100