I am a digit in each of the numerals: 756 657 576. My value is different in all three numerals. What digit am I? What value do I stand for in each numeral?

The digit must be 7.

Check this chart for the place value of each of the 7s.

http://www.glenallanelementary.ca/article_images/16/place-value-chart1.jpg

To determine the digit in each of the numerals, we need to examine the position of the digits in each number. Let's break down each numeral and identify the digit you are in each case:

756:
- The digit in the hundreds place is 7.
- The digit in the tens place is 5.
- The digit in the ones place is 6.

657:
- The digit in the hundreds place is 6.
- The digit in the tens place is 5.
- The digit in the ones place is 7.

576:
- The digit in the hundreds place is 5.
- The digit in the tens place is 7.
- The digit in the ones place is 6.

Since you mentioned that you are a digit and your value is different in all three numerals, we need to identify a digit that changes in each case. By comparing the digits in each position, we can see that the digit in the hundreds place changes from 7 to 6 to 5. Therefore, you are the digit in the hundreds place.

To summarize:
- In the numeral 756, you are the digit 7 in the hundreds place.
- In the numeral 657, you are the digit 6 in the hundreds place.
- In the numeral 576, you are the digit 5 in the hundreds place.