Expanded form is when you take a number, and add its digits together, reforming the number. For example, 1,523 would be 1,000 + 500 + 20 + 3
Here are a few examples:
2,000 + 400 + 50 + 7 = 2,457
200,000 + 700 + 10 + 2 = 200,712
50,000 + 800 + 50 + 6 = 50,856
60,000,000 + 200,000 + 50,000 + 1,000 + 400 + 20 + 3 = 60,251,423
So, 20,484,163 is equal to
20,000,000 + 400,000 + 80,000 + 4,000 + 100 + 60 + 3 = 20,484,163
I hope I helped!
~Olivia