We're dividing 428971 by 217 
The aim is to understand the frequency of 217 in 428971.

Step 1:
217 can be fit into 4 0 times, resulting in a remainder of 4.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 4 to get 4.
Take the next digit (2) from the dividend and append it to 4, then repeat: 42 / 217

Going ahead to step 2:
The number 217 fits into 42 0 times, leaving a remainder of 42.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 42 after subtracting 0 from 42.
Bring next digit (8) of the dividend behind the 42 and repeat the process: 428 / 217

Let's proceed to step 3:
217 can be fit into 428 1 times, resulting in a remainder of 211.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
If we take 217 away from 428, we end up with 211.
Append the next digit (9) from the dividend to 211 and continue with: 2119 / 217

Advancing to step 4:
217 can be fit into 2119 9 times, resulting in a remainder of 166.
Write down 9 as next digit of the result. 
Result so far: 19.0
If we take 1953 away from 2119, we end up with 166.
Append the next digit (7) from the dividend to 166 and continue with: 1667 / 217

Advancing to step 5:
If we divide 1667 by 217, we get 7 and a remainder of 148.
Record the quotient 7 as the next digit in the result. 
Result so far: 197.0
The remainder is 148 after subtracting 1519 from 1667.
Take the next digit (1) from the dividend and append it to 148, then repeat: 1481 / 217

On to step 6:
The number 217 fits into 1481 6 times, leaving a remainder of 179.
Use 6 as the next digit of our solution. 
Result so far: 1976.0
Deduct 1302 from 1481 and we're left with 179.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1790, and continue the process.

On to step 7:
The number 217 fits into 1790 8 times, leaving a remainder of 54.
Put 8 as the next digit of the answer. 
Result so far: 1976.8
Subtract 1736 from 1790 to get 54.
Since there are no more digits in the dividend, we add a zero to the remainder making it 540, and continue the process.

On to step 8:
217 can be fit into 540 2 times, resulting in a remainder of 106.
The next digit of our result is 2. 
Result so far: 1976.82
If we subtract 434 from 540, we get 106.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1060, and continue the process.

Step 9:
1060 divided by 217 is 4 with a remainder of 192.
Use 4 as the next digit of our solution. 
Result so far: 1976.824
The remainder is 192 after subtracting 868 from 1060.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1920, and continue the process.

Moving on to step 10:
217 goes into 1920 8 times with a remainder of 184.
The next digit of our result is 8. 
Result so far: 1976.8248
The remainder is 184 after subtracting 1736 from 1920.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1840, and continue the process.

Moving on to step 11:
When dividing 1840 by 217, we get 8 with a remainder of 104.
The next digit of our result is 8. 
Result so far: 1976.82488
The remainder is 104 after subtracting 1736 from 1840.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1040, and continue the process.

After the division, we end up with 1976.82488 and a remainder of 0.000104.