We're dividing 39851473 by 509 
The aim is to understand the frequency of 509 in 39851473.

Going ahead to step 1:
509 goes into 3 0 times with a remainder of 3.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 3 after subtracting 0 from 3.
Append the next digit (9) from the dividend to 3 and continue with: 39 / 509

Moving on to step 2:
When dividing 39 by 509, we get 0 with a remainder of 39.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 39, we end up with 39.
Fetch the next digit (8) from the dividend, attach it to 39 and continue: 398 / 509

On to step 3:
The number 509 fits into 398 0 times, leaving a remainder of 398.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 398, we end up with 398.
Append the next digit (5) from the dividend to 398 and continue with: 3985 / 509

Going ahead to step 4:
509 goes into 3985 7 times with a remainder of 422.
Record the quotient 7 as the next digit in the result. 
Result so far: 7.0
If we subtract 3563 from 3985, we get 422.
Bring next digit (1) of the dividend behind the 422 and repeat the process: 4221 / 509

Moving on to step 5:
509 can be fit into 4221 8 times, resulting in a remainder of 149.
Record the quotient 8 as the next digit in the result. 
Result so far: 78.0
The remainder is 149 after subtracting 4072 from 4221.
Grab the next digit (4) from the dividend, add it to 149, then carry on: 1494 / 509

On to step 6:
When dividing 1494 by 509, we get 2 with a remainder of 476.
Put 2 as the next digit of the answer. 
Result so far: 782.0
Subtract 1018 from 1494 to get 476.
Grab the next digit (7) from the dividend, add it to 476, then carry on: 4767 / 509

Step 7:
If we divide 4767 by 509, we get 9 and a remainder of 186.
Use 9 as the next digit of our solution. 
Result so far: 7829.0
Deduct 4581 from 4767 and we're left with 186.
Append the next digit (3) from the dividend to 186 and continue with: 1863 / 509

Advancing to step 8:
If we divide 1863 by 509, we get 3 and a remainder of 336.
Put 3 as the next digit of the answer. 
Result so far: 78293.0
Subtracting 1527 from 1863 leaves us with 336.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3360, and continue the process.

Step 9:
When dividing 3360 by 509, we get 6 with a remainder of 306.
Write down 6 as next digit of the result. 
Result so far: 78293.6
If we subtract 3054 from 3360, we get 306.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3060, and continue the process.

Going ahead to step 10:
If we divide 3060 by 509, we get 6 and a remainder of 6.
Record the quotient 6 as the next digit in the result. 
Result so far: 78293.66
Subtract 3054 from 3060 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

The quotient of the division is 78293.66, and the remainder is 0.006.