138784 divided by 78 
The aim is to understand the frequency of 78 in 138784.

Moving on to step 1:
When dividing 1 by 78, we get 0 with a remainder of 1.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 1 leaves us with 1.
Include the next digit (3) from the dividend after 1, then repeat: 13 / 78

Step 2:
If we divide 13 by 78, we get 0 and a remainder of 13.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 13, we end up with 13.
Grab the next digit (8) from the dividend, add it to 13, then carry on: 138 / 78

On to step 3:
If we divide 138 by 78, we get 1 and a remainder of 60.
Use 1 as the next digit of our solution. 
Result so far: 1.0
If we subtract 78 from 138, we get 60.
Include the next digit (7) from the dividend after 60, then repeat: 607 / 78

On to step 4:
607 divided by 78 is 7 with a remainder of 61.
The next digit of our result is 7. 
Result so far: 17.0
Deduct 546 from 607 and we're left with 61.
Bring next digit (8) of the dividend behind the 61 and repeat the process: 618 / 78

Advancing to step 5:
The number 78 fits into 618 7 times, leaving a remainder of 72.
Put 7 as the next digit of the answer. 
Result so far: 177.0
The remainder is 72 after subtracting 546 from 618.
Fetch the next digit (4) from the dividend, attach it to 72 and continue: 724 / 78

On to step 6:
724 divided by 78 is 9 with a remainder of 22.
Put 9 as the next digit of the answer. 
Result so far: 1779.0
If we subtract 702 from 724, we get 22.
Since there are no more digits in the dividend, we add a zero to the remainder making it 220, and continue the process.

Moving on to step 7:
The number 78 fits into 220 2 times, leaving a remainder of 64.
The number 2 becomes the next digit in our result. 
Result so far: 1779.2
The remainder is 64 after subtracting 156 from 220.
Since there are no more digits in the dividend, we add a zero to the remainder making it 640, and continue the process.

Going ahead to step 8:
78 can be fit into 640 8 times, resulting in a remainder of 16.
Record the quotient 8 as the next digit in the result. 
Result so far: 1779.28
If we take 624 away from 640, we end up with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

On to step 9:
78 can be fit into 160 2 times, resulting in a remainder of 4.
The number 2 becomes the next digit in our result. 
Result so far: 1779.282
Deduct 156 from 160 and we're left with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Step 10:
78 goes into 40 0 times with a remainder of 40.
The number 0 becomes the next digit in our result. 
Result so far: 1779.282
Subtract 0 from 40 to 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.

Let's proceed to step 11:
78 can be fit into 400 5 times, resulting in a remainder of 10.
The number 5 becomes the next digit in our result. 
Result so far: 1779.28205
If we take 390 away from 400, we end up 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:
The number 78 fits into 100 1 times, leaving a remainder of 22.
Record the quotient 1 as the next digit in the result. 
Result so far: 1779.282051
The remainder is 22 after subtracting 78 from 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 220, and continue the process.

Let's proceed to step 13:
78 can be fit into 220 2 times, resulting in a remainder of 64.
Write down 2 as next digit of the result. 
Result so far: 1779.2820512
If we subtract 156 from 220, we get 64.
Since there are no more digits in the dividend, we add a zero to the remainder making it 640, and continue the process.

Moving on to step 14:
78 goes into 640 8 times with a remainder of 16.
The next digit of our result is 8. 
Result so far: 1779.28205128
If we take 624 away from 640, we end up with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

The final outcome is 1779.28205128, with a leftover of 1.6e-08.