We look at the division of 43217984 by 423 
The aim is to understand the frequency of 423 in 43217984.

On to step 1:
When dividing 4 by 423, we get 0 with a remainder of 4.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 4 after subtracting 0 from 4.
Fetch the next digit (3) from the dividend, attach it to 4 and continue: 43 / 423

Step 2:
If we divide 43 by 423, we get 0 and a remainder of 43.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 43, we end up with 43.
Append the next digit (2) from the dividend to 43 and continue with: 432 / 423

Let's proceed to step 3:
423 goes into 432 1 times with a remainder of 9.
Write down 1 as next digit of the result. 
Result so far: 1.0
If we take 423 away from 432, we end up with 9.
Grab the next digit (1) from the dividend, add it to 9, then carry on: 91 / 423

On to step 4:
The number 423 fits into 91 0 times, leaving a remainder of 91.
Record the quotient 0 as the next digit in the result. 
Result so far: 10.0
Subtracting 0 from 91 leaves us with 91.
Fetch the next digit (7) from the dividend, attach it to 91 and continue: 917 / 423

Advancing to step 5:
423 goes into 917 2 times with a remainder of 71.
The number 2 becomes the next digit in our result. 
Result so far: 102.0
Deduct 846 from 917 and we're left with 71.
Fetch the next digit (9) from the dividend, attach it to 71 and continue: 719 / 423

Advancing to step 6:
423 goes into 719 1 times with a remainder of 296.
Use 1 as the next digit of our solution. 
Result so far: 1021.0
If we take 423 away from 719, we end up with 296.
Grab the next digit (8) from the dividend, add it to 296, then carry on: 2968 / 423

Going ahead to step 7:
The number 423 fits into 2968 7 times, leaving a remainder of 7.
Record the quotient 7 as the next digit in the result. 
Result so far: 10217.0
Subtract 2961 from 2968 to get 7.
Take the next digit (4) from the dividend and append it to 7, then repeat: 74 / 423

Going ahead to step 8:
When dividing 74 by 423, we get 0 with a remainder of 74.
Write down 0 as next digit of the result. 
Result so far: 102170.0
Subtract 0 from 74 to get 74.
Since there are no more digits in the dividend, we add a zero to the remainder making it 740, and continue the process.

Moving on to step 9:
When dividing 740 by 423, we get 1 with a remainder of 317.
The next digit of our result is 1. 
Result so far: 102170.1
Deduct 423 from 740 and we're left with 317.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3170, and continue the process.

On to step 10:
423 can be fit into 3170 7 times, resulting in a remainder of 209.
Use 7 as the next digit of our solution. 
Result so far: 102170.17
Subtracting 2961 from 3170 leaves us with 209.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2090, and continue the process.

Moving on to step 11:
2090 divided by 423 is 4 with a remainder of 398.
Put 4 as the next digit of the answer. 
Result so far: 102170.174
Deduct 1692 from 2090 and we're left with 398.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3980, and continue the process.

Advancing to step 12:
423 can be fit into 3980 9 times, resulting in a remainder of 173.
The number 9 becomes the next digit in our result. 
Result so far: 102170.1749
Deduct 3807 from 3980 and we're left with 173.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1730, and continue the process.

Step 13:
When dividing 1730 by 423, we get 4 with a remainder of 38.
The number 4 becomes the next digit in our result. 
Result so far: 102170.17494
Deduct 1692 from 1730 and we're left with 38.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

Going ahead to step 14:
The number 423 fits into 380 0 times, leaving a remainder of 380.
The next digit of our result is 0. 
Result so far: 102170.17494
Deduct 0 from 380 and we're left with 380.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3800, and continue the process.

On to step 15:
3800 divided by 423 is 8 with a remainder of 416.
Use 8 as the next digit of our solution. 
Result so far: 102170.1749408
Deduct 3384 from 3800 and we're left with 416.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4160, and continue the process.

Going ahead to step 16:
When dividing 4160 by 423, we get 9 with a remainder of 353.
Put 9 as the next digit of the answer. 
Result so far: 102170.17494089
If we take 3807 away from 4160, we end up with 353.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3530, and continue the process.

The final result is 102170.17494089 with a remainder of 3.53e-07.