The place value of the digit 3 in the number 983456 is 3,000.
The reason for this is because the place value is located in the position of the 1,000 family. The 6 would be in the ones place, the 5 would be in the tens place, the 4 is in the hundreds place, therefore, the 3 is in the 1000's place making it a three-thousand.
Similarly,the number 8 is in the 10,000 place making it an 80,000 (eighty thousand) and the 9 is located in the hundred thousand (100,000) position making it a 900,000.
The best way to deal with place value is writing down the numbers in word form so that you can "say aloud" the place in which each number is. In this case, it would be:
Nine hundred and eighty three thousand, four hundred and fifty six. In the long run, it would be easier this way.