The digit 4 in 475 is in the hundreds place value. It represents 400 because in a three-digit number, the first digit from the left is the hundreds. The digit 7 is in the tens place, representing 70, and the digit 5 is in the ones place, representing 5. Place value is important because it gives meaning to each digit in a number. Without it, we cannot distinguish between 4, 40, and 400.