To determine how many different license plates are possible, let's break the problem down into two parts:

1. Digits (numbers): The plate contains 4 digits. Each digit can be any number from 0 to 9, which gives us 10 possible choices per digit. Since there are 4 digits, the total number of possible combinations of digits is:

   $10 \times 10 \times 10 \times 10 = 10^4 = 10,000$

2. Letters: The plate also contains 3 letters. Each letter can be any letter from A to Z, which gives us 26 possible choices per letter. Since there are 3 letters, the total number of possible combinations of letters is:

   $26 \times 26 \times 26 = 26^3 = 17,576$

Now, to find the total number of different license plates, multiply the total possibilities for the digits by the total possibilities for the letters:

$10,000 \times 17,576 = 175,760,000$

So, the total number of different standard plates possible in this system is 175,760,000.

Would you like further clarification or details on any of these steps?

Here are 5 related questions to expand this concept:

1. What if the state restricted the first digit to be non-zero? How many plates would be possible then?
2. How would the number of plates change if repetitions of letters were not allowed?
3. What if the state used 5 digits and 2 letters instead? How many plates would be possible?
4. If one digit and one letter were pre-fixed (e.g., "5A"), how many plates could be created?
5. How would the system change if only specific letters (e.g., excluding vowels) were allowed?

Tip: When solving problems involving combinations, break the problem into smaller parts (e.g., digits and letters), and apply the multiplication rule of counting to get the total number of possibilities.