Can you me understand this? in the number 7,725, which places contain digits where one digit is ten times as great as the other?

You can break this down pretty easily (though I know it sounds confusing). First, you seperate all of the digits:
7,725 -> 5, 20, 700, and 7,000

Now, which ones have a difference of a factor of 10? Well, 700 * 10 = 7,000, so the answer would be: The hundredths place. Hope I helped!

7,725 the 1st number in the digits is the ones place and the 2nd number is in the tens place and the 3rd number is in the hundreds place and the 4th nmber is in the thousands place.