78139751 ÷ 840 
The aim is to understand the frequency of 840 in 78139751.

Advancing to step 1:
If we divide 7 by 840, we get 0 and a remainder of 7.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 7 after subtracting 0 from 7.
Bring next digit (8) of the dividend behind the 7 and repeat the process: 78 / 840

Going ahead to step 2:
The number 840 fits into 78 0 times, leaving a remainder of 78.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 78 and we're left with 78.
Append the next digit (1) from the dividend to 78 and continue with: 781 / 840

Going ahead to step 3:
840 can be fit into 781 0 times, resulting in a remainder of 781.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 781, we get 781.
Include the next digit (3) from the dividend after 781, then repeat: 7813 / 840

Moving on to step 4:
840 goes into 7813 9 times with a remainder of 253.
Put 9 as the next digit of the answer. 
Result so far: 9.0
If we take 7560 away from 7813, we end up with 253.
Append the next digit (9) from the dividend to 253 and continue with: 2539 / 840

Let's proceed to step 5:
2539 divided by 840 is 3 with a remainder of 19.
The number 3 becomes the next digit in our result. 
Result so far: 93.0
The remainder is 19 after subtracting 2520 from 2539.
Bring next digit (7) of the dividend behind the 19 and repeat the process: 197 / 840

Moving on to step 6:
The number 840 fits into 197 0 times, leaving a remainder of 197.
Write down 0 as next digit of the result. 
Result so far: 930.0
The remainder is 197 after subtracting 0 from 197.
Take the next digit (5) from the dividend and append it to 197, then repeat: 1975 / 840

Moving on to step 7:
840 goes into 1975 2 times with a remainder of 295.
The next digit of our result is 2. 
Result so far: 9302.0
Subtracting 1680 from 1975 leaves us with 295.
Append the next digit (1) from the dividend to 295 and continue with: 2951 / 840

Advancing to step 8:
2951 divided by 840 is 3 with a remainder of 431.
The next digit of our result is 3. 
Result so far: 93023.0
Subtract 2520 from 2951 to get 431.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4310, and continue the process.

On to step 9:
840 can be fit into 4310 5 times, resulting in a remainder of 110.
The number 5 becomes the next digit in our result. 
Result so far: 93023.5
The remainder is 110 after subtracting 4200 from 4310.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1100, and continue the process.

Going ahead to step 10:
1100 divided by 840 is 1 with a remainder of 260.
The next digit of our result is 1. 
Result so far: 93023.51
If we take 840 away from 1100, we end up with 260.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2600, and continue the process.

Going ahead to step 11:
840 can be fit into 2600 3 times, resulting in a remainder of 80.
Use 3 as the next digit of our solution. 
Result so far: 93023.513
If we take 2520 away from 2600, we end up with 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 800, and continue the process.

Let's proceed to step 12:
840 goes into 800 0 times with a remainder of 800.
The number 0 becomes the next digit in our result. 
Result so far: 93023.513
If we subtract 0 from 800, we get 800.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8000, and continue the process.

Going ahead to step 13:
840 goes into 8000 9 times with a remainder of 440.
Put 9 as the next digit of the answer. 
Result so far: 93023.51309
If we subtract 7560 from 8000, we get 440.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4400, and continue the process.

Going ahead to step 14:
4400 divided by 840 is 5 with a remainder of 200.
Put 5 as the next digit of the answer. 
Result so far: 93023.513095
If we subtract 4200 from 4400, we get 200.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2000, and continue the process.

Step 15:
If we divide 2000 by 840, we get 2 and a remainder of 320.
The number 2 becomes the next digit in our result. 
Result so far: 93023.5130952
Subtracting 1680 from 2000 leaves us with 320.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3200, and continue the process.

Let's proceed to step 16:
840 goes into 3200 3 times with a remainder of 680.
The next digit of our result is 3. 
Result so far: 93023.51309523
Subtract 2520 from 3200 to get 680.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6800, and continue the process.

In conclusion, the division gives 93023.51309523 with a balance of 6.8e-07.