71785900 ÷ 210 
The aim is to understand the frequency of 210 in 71785900.

Let's proceed to step 1:
210 goes into 7 0 times with a remainder of 7.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 7 and we're left with 7.
Take the next digit (1) from the dividend and append it to 7, then repeat: 71 / 210

On to step 2:
210 can be fit into 71 0 times, resulting in a remainder of 71.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 71 to get 71.
Fetch the next digit (7) from the dividend, attach it to 71 and continue: 717 / 210

Step 3:
210 goes into 717 3 times with a remainder of 87.
The next digit of our result is 3. 
Result so far: 3.0
If we take 630 away from 717, we end up with 87.
Append the next digit (8) from the dividend to 87 and continue with: 878 / 210

Step 4:
878 divided by 210 is 4 with a remainder of 38.
The number 4 becomes the next digit in our result. 
Result so far: 34.0
Subtract 840 from 878 to get 38.
Grab the next digit (5) from the dividend, add it to 38, then carry on: 385 / 210

On to step 5:
385 divided by 210 is 1 with a remainder of 175.
The next digit of our result is 1. 
Result so far: 341.0
If we take 210 away from 385, we end up with 175.
Take the next digit (9) from the dividend and append it to 175, then repeat: 1759 / 210

Step 6:
210 can be fit into 1759 8 times, resulting in a remainder of 79.
The next digit of our result is 8. 
Result so far: 3418.0
Subtracting 1680 from 1759 leaves us with 79.
Include the next digit (0) from the dividend after 79, then repeat: 790 / 210

On to step 7:
210 can be fit into 790 3 times, resulting in a remainder of 160.
The number 3 becomes the next digit in our result. 
Result so far: 34183.0
If we take 630 away from 790, we end up with 160.
Include the next digit (0) from the dividend after 160, then repeat: 1600 / 210

Moving on to step 8:
If we divide 1600 by 210, we get 7 and a remainder of 130.
Record the quotient 7 as the next digit in the result. 
Result so far: 341837.0
Subtract 1470 from 1600 to get 130.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1300, and continue the process.

Advancing to step 9:
210 goes into 1300 6 times with a remainder of 40.
Put 6 as the next digit of the answer. 
Result so far: 341837.6
Subtracting 1260 from 1300 leaves us with 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Moving on to step 10:
210 can be fit into 400 1 times, resulting in a remainder of 190.
Write down 1 as next digit of the result. 
Result so far: 341837.61
Subtract 210 from 400 to get 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1900, and continue the process.

Advancing to step 11:
210 can be fit into 1900 9 times, resulting in a remainder of 10.
Put 9 as the next digit of the answer. 
Result so far: 341837.619
Deduct 1890 from 1900 and we're left with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Let's proceed to step 12:
210 goes into 100 0 times with a remainder of 100.
The next digit of our result is 0. 
Result so far: 341837.619
If we take 0 away from 100, we end up with 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1000, and continue the process.

On to step 13:
The number 210 fits into 1000 4 times, leaving a remainder of 160.
Write down 4 as next digit of the result. 
Result so far: 341837.61904
If we take 840 away from 1000, we end up with 160.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1600, and continue the process.

On to step 14:
If we divide 1600 by 210, we get 7 and a remainder of 130.
Write down 7 as next digit of the result. 
Result so far: 341837.619047
The remainder is 130 after subtracting 1470 from 1600.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1300, and continue the process.

On to step 15:
The number 210 fits into 1300 6 times, leaving a remainder of 40.
Put 6 as the next digit of the answer. 
Result so far: 341837.6190476
If we subtract 1260 from 1300, we get 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Advancing to step 16:
When dividing 400 by 210, we get 1 with a remainder of 190.
Write down 1 as next digit of the result. 
Result so far: 341837.61904761
If we subtract 210 from 400, we get 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1900, and continue the process.

The final outcome is 341837.61904761, with a leftover of 1.9e-07.