10121880 ÷ 401 
The aim is to understand the frequency of 401 in 10121880.

Moving on to step 1:
If we divide 1 by 401, we get 0 and a remainder of 1.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 1 after subtracting 0 from 1.
Grab the next digit (0) from the dividend, add it to 1, then carry on: 10 / 401

Advancing to step 2:
If we divide 10 by 401, we get 0 and a remainder of 10.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 10, we get 10.
Append the next digit (1) from the dividend to 10 and continue with: 101 / 401

Going ahead to step 3:
101 divided by 401 is 0 with a remainder of 101.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 101 and we're left with 101.
Bring next digit (2) of the dividend behind the 101 and repeat the process: 1012 / 401

Moving on to step 4:
When dividing 1012 by 401, we get 2 with a remainder of 210.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
If we take 802 away from 1012, we end up with 210.
Fetch the next digit (1) from the dividend, attach it to 210 and continue: 2101 / 401

Advancing to step 5:
401 can be fit into 2101 5 times, resulting in a remainder of 96.
Put 5 as the next digit of the answer. 
Result so far: 25.0
Deduct 2005 from 2101 and we're left with 96.
Bring next digit (8) of the dividend behind the 96 and repeat the process: 968 / 401

Let's proceed to step 6:
If we divide 968 by 401, we get 2 and a remainder of 166.
Put 2 as the next digit of the answer. 
Result so far: 252.0
The remainder is 166 after subtracting 802 from 968.
Include the next digit (8) from the dividend after 166, then repeat: 1668 / 401

Going ahead to step 7:
When dividing 1668 by 401, we get 4 with a remainder of 64.
The next digit of our result is 4. 
Result so far: 2524.0
The remainder is 64 after subtracting 1604 from 1668.
Include the next digit (0) from the dividend after 64, then repeat: 640 / 401

On to step 8:
If we divide 640 by 401, we get 1 and a remainder of 239.
Write down 1 as next digit of the result. 
Result so far: 25241.0
If we subtract 401 from 640, we get 239.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2390, and continue the process.

Let's proceed to step 9:
When dividing 2390 by 401, we get 5 with a remainder of 385.
Use 5 as the next digit of our solution. 
Result so far: 25241.5
The remainder is 385 after subtracting 2005 from 2390.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3850, and continue the process.

Advancing to step 10:
If we divide 3850 by 401, we get 9 and a remainder of 241.
Write down 9 as next digit of the result. 
Result so far: 25241.59
Subtracting 3609 from 3850 leaves us with 241.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2410, and continue the process.

Advancing to step 11:
If we divide 2410 by 401, we get 6 and a remainder of 4.
The next digit of our result is 6. 
Result so far: 25241.596
The remainder is 4 after subtracting 2406 from 2410.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Moving on to step 12:
When dividing 40 by 401, we get 0 with a remainder of 40.
Use 0 as the next digit of our solution. 
Result so far: 25241.596
If we take 0 away from 40, we end up with 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Advancing to step 13:
401 can be fit into 400 0 times, resulting in a remainder of 400.
Write down 0 as next digit of the result. 
Result so far: 25241.596
Subtract 0 from 400 to get 400.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4000, and continue the process.

After the division, we end up with 25241.596 and a remainder of 0.0004.