161561 ÷ 78 
The aim is to understand the frequency of 78 in 161561.

Going ahead 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
Deduct 0 from 1 and we're left with 1.
Grab the next digit (6) from the dividend, add it to 1, then carry on: 16 / 78

Going ahead to step 2:
The number 78 fits into 16 0 times, leaving a remainder of 16.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 16 to get 16.
Include the next digit (1) from the dividend after 16, then repeat: 161 / 78

Let's proceed to step 3:
When dividing 161 by 78, we get 2 with a remainder of 5.
Put 2 as the next digit of the answer. 
Result so far: 2.0
The remainder is 5 after subtracting 156 from 161.
Fetch the next digit (5) from the dividend, attach it to 5 and continue: 55 / 78

On to step 4:
78 can be fit into 55 0 times, resulting in a remainder of 55.
The next digit of our result is 0. 
Result so far: 20.0
If we subtract 0 from 55, we get 55.
Bring next digit (6) of the dividend behind the 55 and repeat the process: 556 / 78

Step 5:
556 divided by 78 is 7 with a remainder of 10.
Write down 7 as next digit of the result. 
Result so far: 207.0
The remainder is 10 after subtracting 546 from 556.
Take the next digit (1) from the dividend and append it to 10, then repeat: 101 / 78

Let's proceed to step 6:
101 divided by 78 is 1 with a remainder of 23.
The number 1 becomes the next digit in our result. 
Result so far: 2071.0
Subtract 78 from 101 to get 23.
Since there are no more digits in the dividend, we add a zero to the remainder making it 230, and continue the process.

Moving on to step 7:
When dividing 230 by 78, we get 2 with a remainder of 74.
Use 2 as the next digit of our solution. 
Result so far: 2071.2
Deduct 156 from 230 and we're left with 74.
Since there are no more digits in the dividend, we add a zero to the remainder making it 740, and continue the process.

Going ahead to step 8:
78 can be fit into 740 9 times, resulting in a remainder of 38.
Use 9 as the next digit of our solution. 
Result so far: 2071.29
Subtracting 702 from 740 leaves us with 38.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

Moving on to step 9:
380 divided by 78 is 4 with a remainder of 68.
The next digit of our result is 4. 
Result so far: 2071.294
Deduct 312 from 380 and we're left with 68.
Since there are no more digits in the dividend, we add a zero to the remainder making it 680, and continue the process.

Going ahead to step 10:
680 divided by 78 is 8 with a remainder of 56.
Write down 8 as next digit of the result. 
Result so far: 2071.2948
Subtracting 624 from 680 leaves us with 56.
Since there are no more digits in the dividend, we add a zero to the remainder making it 560, and continue the process.

Advancing to step 11:
When dividing 560 by 78, we get 7 with a remainder of 14.
Use 7 as the next digit of our solution. 
Result so far: 2071.29487
Subtracting 546 from 560 leaves us with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Moving on to step 12:
78 can be fit into 140 1 times, resulting in a remainder of 62.
Put 1 as the next digit of the answer. 
Result so far: 2071.294871
If we subtract 78 from 140, we get 62.
Since there are no more digits in the dividend, we add a zero to the remainder making it 620, and continue the process.

Moving on to step 13:
620 divided by 78 is 7 with a remainder of 74.
Put 7 as the next digit of the answer. 
Result so far: 2071.2948717
Subtracting 546 from 620 leaves us with 74.
Since there are no more digits in the dividend, we add a zero to the remainder making it 740, and continue the process.

Advancing to step 14:
78 can be fit into 740 9 times, resulting in a remainder of 38.
Use 9 as the next digit of our solution. 
Result so far: 2071.29487179
Deduct 702 from 740 and we're left with 38.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

The final outcome is 2071.29487179, with a leftover of 3.8e-08.