Final answer:
To find the number of different four-digit multiples of 10, calculate 9 options for the first digit, 10 for the second, 10 for the third, and only 1 for the fourth digit, yielding 900 unique numbers.
Step-by-step explanation:
The question is about finding out how many different four-digit numbers that are multiples of 10 can be formed. We know that any multiple of 10 must end in a zero, so the last digit is fixed. The remaining three digits can range from 1 to 9 for the first digit (since a number can't start with zero to be a four-digit number) and 0 to 9 for the other two digits (including zero). Therefore, using the multiplication principle, we calculate the number of possibilities as 9 (choices for the first digit) × 10 (choices for the second digit) × 10 (choices for the third digit) × 1 (choice for the fourth digit, which has to be 0). This results in 9 × 10 × 10 × 1 = 900 possible four-digit numbers that are multiples of 10.