The expanded form of a power of ten is like modeling the expanded for mhm of a normal number but in terms of powers of ten. Here, I will demonstrate by showing you an example. Here is the expanded form of 1,000:
1,000.
Why? Well, the expanded form of 1,000 is itself because it is in a digits place notable for being able to do expanded form in. There are the ones place, tens place, hundreds place, and thousands place. Because ten to the third power is 1,000, the number itself is representative of its own expanded form. This varies for numbers that are different though. Another example would be as follows; the number 1,783. Here is the expanded form of that number:
1,000 + 700 + 80 + 3
Remember the digits places I mentioned above (ones, tens, hundreds, and thousands)? Those come in handy for these kinds of numbers. 1 is in the thousands place so the number is 1,000. 7 is in the hundreds place so the number is 700. 80 is in the tens place so the number is 80. Lastly, 3 is in the ones place so the number is 3. An easy way to remember expanded form is to just take the number by what digits place it is in, and multiply it by the corresponding digit value that it is in. For example, to get 80, we can do 8 x 10 because we are multiplying the 8 that is in the tens place by the digit place it is in, which happens to be the tens place. If you need to better understand, let me know and I will gladly assist you!