Let's divide 51396581 by 945
The aim is to understand the frequency of 945 in 51396581.

Advancing to step 1:
The number 945 fits into 5 0 times, leaving a remainder of 5.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 5, we get 5.
Append the next digit (1) from the dividend to 5 and continue with: 51 / 945

On to step 2:
If we divide 51 by 945, we get 0 and a remainder of 51.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 51 after subtracting 0 from 51.
Include the next digit (3) from the dividend after 51, then repeat: 513 / 945

Advancing to step 3:
945 goes into 513 0 times with a remainder of 513.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 513 and we're left with 513.
Include the next digit (9) from the dividend after 513, then repeat: 5139 / 945

Going ahead to step 4:
When dividing 5139 by 945, we get 5 with a remainder of 414.
Record the quotient 5 as the next digit in the result. 
Result so far: 5.0
If we take 4725 away from 5139, we end up with 414.
Grab the next digit (6) from the dividend, add it to 414, then carry on: 4146 / 945

Step 5:
945 can be fit into 4146 4 times, resulting in a remainder of 366.
Put 4 as the next digit of the answer. 
Result so far: 54.0
The remainder is 366 after subtracting 3780 from 4146.
Include the next digit (5) from the dividend after 366, then repeat: 3665 / 945

Going ahead to step 6:
3665 divided by 945 is 3 with a remainder of 830.
Write down 3 as next digit of the result. 
Result so far: 543.0
Deduct 2835 from 3665 and we're left with 830.
Append the next digit (8) from the dividend to 830 and continue with: 8308 / 945

On to step 7:
945 can be fit into 8308 8 times, resulting in a remainder of 748.
The number 8 becomes the next digit in our result. 
Result so far: 5438.0
Subtracting 7560 from 8308 leaves us with 748.
Append the next digit (1) from the dividend to 748 and continue with: 7481 / 945

Going ahead to step 8:
945 goes into 7481 7 times with a remainder of 866.
Write down 7 as next digit of the result. 
Result so far: 54387.0
If we subtract 6615 from 7481, we get 866.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8660, and continue the process.

Going ahead to step 9:
If we divide 8660 by 945, we get 9 and a remainder of 155.
Put 9 as the next digit of the answer. 
Result so far: 54387.9
Subtracting 8505 from 8660 leaves us with 155.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1550, and continue the process.

Going ahead to step 10:
945 can be fit into 1550 1 times, resulting in a remainder of 605.
Put 1 as the next digit of the answer. 
Result so far: 54387.91
Subtracting 945 from 1550 leaves us with 605.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6050, and continue the process.

Moving on to step 11:
945 can be fit into 6050 6 times, resulting in a remainder of 380.
Write down 6 as next digit of the result. 
Result so far: 54387.916
Subtract 5670 from 6050 to get 380.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3800, and continue the process.

Advancing to step 12:
945 can be fit into 3800 4 times, resulting in a remainder of 20.
The number 4 becomes the next digit in our result. 
Result so far: 54387.9164
If we subtract 3780 from 3800, we get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

On to step 13:
945 can be fit into 200 0 times, resulting in a remainder of 200.
The number 0 becomes the next digit in our result. 
Result so far: 54387.9164
Deduct 0 from 200 and we're left with 200.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2000, and continue the process.

Let's proceed to step 14:
2000 divided by 945 is 2 with a remainder of 110.
The next digit of our result is 2. 
Result so far: 54387.916402
Subtract 1890 from 2000 to get 110.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1100, and continue the process.

On to step 15:
1100 divided by 945 is 1 with a remainder of 155.
Record the quotient 1 as the next digit in the result. 
Result so far: 54387.9164021
If we subtract 945 from 1100, we get 155.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1550, and continue the process.

On to step 16:
If we divide 1550 by 945, we get 1 and a remainder of 605.
Use 1 as the next digit of our solution. 
Result so far: 54387.91640211
Deduct 945 from 1550 and we're left with 605.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6050, and continue the process.

The final outcome is 54387.91640211, with a leftover of 6.05e-07.