We're dividing 78105015 by 243 
The aim is to understand the frequency of 243 in 78105015.

Going ahead to step 1:
When dividing 7 by 243, we get 0 with a remainder of 7.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 7 to get 7.
Take the next digit (8) from the dividend and append it to 7, then repeat: 78 / 243

On to step 2:
If we divide 78 by 243, we get 0 and a remainder of 78.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 78 to get 78.
Take the next digit (1) from the dividend and append it to 78, then repeat: 781 / 243

Step 3:
The number 243 fits into 781 3 times, leaving a remainder of 52.
Record the quotient 3 as the next digit in the result. 
Result so far: 3.0
The remainder is 52 after subtracting 729 from 781.
Take the next digit (0) from the dividend and append it to 52, then repeat: 520 / 243

Step 4:
The number 243 fits into 520 2 times, leaving a remainder of 34.
Use 2 as the next digit of our solution. 
Result so far: 32.0
The remainder is 34 after subtracting 486 from 520.
Append the next digit (5) from the dividend to 34 and continue with: 345 / 243

On to step 5:
243 can be fit into 345 1 times, resulting in a remainder of 102.
Record the quotient 1 as the next digit in the result. 
Result so far: 321.0
Subtracting 243 from 345 leaves us with 102.
Append the next digit (0) from the dividend to 102 and continue with: 1020 / 243

On to step 6:
When dividing 1020 by 243, we get 4 with a remainder of 48.
Put 4 as the next digit of the answer. 
Result so far: 3214.0
Subtracting 972 from 1020 leaves us with 48.
Grab the next digit (1) from the dividend, add it to 48, then carry on: 481 / 243

Advancing to step 7:
243 can be fit into 481 1 times, resulting in a remainder of 238.
The next digit of our result is 1. 
Result so far: 32141.0
Subtracting 243 from 481 leaves us with 238.
Fetch the next digit (5) from the dividend, attach it to 238 and continue: 2385 / 243

Going ahead to step 8:
2385 divided by 243 is 9 with a remainder of 198.
Write down 9 as next digit of the result. 
Result so far: 321419.0
The remainder is 198 after subtracting 2187 from 2385.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1980, and continue the process.

Advancing to step 9:
The number 243 fits into 1980 8 times, leaving a remainder of 36.
Use 8 as the next digit of our solution. 
Result so far: 321419.8
Subtracting 1944 from 1980 leaves us with 36.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

Going ahead to step 10:
When dividing 360 by 243, we get 1 with a remainder of 117.
Record the quotient 1 as the next digit in the result. 
Result so far: 321419.81
If we subtract 243 from 360, we get 117.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1170, and continue the process.

Going ahead to step 11:
If we divide 1170 by 243, we get 4 and a remainder of 198.
Use 4 as the next digit of our solution. 
Result so far: 321419.814
The remainder is 198 after subtracting 972 from 1170.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1980, and continue the process.

Moving on to step 12:
243 can be fit into 1980 8 times, resulting in a remainder of 36.
The next digit of our result is 8. 
Result so far: 321419.8148
Subtracting 1944 from 1980 leaves us with 36.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

Moving on to step 13:
The number 243 fits into 360 1 times, leaving a remainder of 117.
Use 1 as the next digit of our solution. 
Result so far: 321419.81481
Subtracting 243 from 360 leaves us with 117.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1170, and continue the process.

Step 14:
243 can be fit into 1170 4 times, resulting in a remainder of 198.
The number 4 becomes the next digit in our result. 
Result so far: 321419.814814
If we take 972 away from 1170, we end up with 198.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1980, and continue the process.

Step 15:
243 goes into 1980 8 times with a remainder of 36.
The next digit of our result is 8. 
Result so far: 321419.8148148
The remainder is 36 after subtracting 1944 from 1980.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

On to step 16:
243 can be fit into 360 1 times, resulting in a remainder of 117.
The number 1 becomes the next digit in our result. 
Result so far: 321419.81481481
Subtract 243 from 360 to get 117.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1170, and continue the process.

After the division, we end up with 321419.81481481 and a remainder of 1.17e-07.