1221851 ÷ 100 
Let's see how many times 100 fits into 1221851.

Moving on to step 1:
100 goes into 1 0 times with a remainder of 1.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 1 to get 1.
Take the next digit (2) from the dividend and append it to 1, then repeat: 12 / 100

Going ahead to step 2:
12 divided by 100 is 0 with a remainder of 12.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 12 to get 12.
Include the next digit (2) from the dividend after 12, then repeat: 122 / 100

Advancing to step 3:
122 divided by 100 is 1 with a remainder of 22.
Write down 1 as next digit of the result. 
Result so far: 1.0
If we subtract 100 from 122, we get 22.
Grab the next digit (1) from the dividend, add it to 22, then carry on: 221 / 100

On to step 4:
When dividing 221 by 100, we get 2 with a remainder of 21.
Write down 2 as next digit of the result. 
Result so far: 12.0
Subtract 200 from 221 to get 21.
Fetch the next digit (8) from the dividend, attach it to 21 and continue: 218 / 100

Going ahead to step 5:
The number 100 fits into 218 2 times, leaving a remainder of 18.
Use 2 as the next digit of our solution. 
Result so far: 122.0
If we subtract 200 from 218, we get 18.
Take the next digit (5) from the dividend and append it to 18, then repeat: 185 / 100

Advancing to step 6:
100 goes into 185 1 times with a remainder of 85.
Put 1 as the next digit of the answer. 
Result so far: 1221.0
Subtracting 100 from 185 leaves us with 85.
Append the next digit (1) from the dividend to 85 and continue with: 851 / 100

Moving on to step 7:
851 divided by 100 is 8 with a remainder of 51.
The next digit of our result is 8. 
Result so far: 12218.0
If we subtract 800 from 851, we get 51.
Since there are no more digits in the dividend, we add a zero to the remainder making it 510, and continue the process.

Moving on to step 8:
When dividing 510 by 100, we get 5 with a remainder of 10.
The next digit of our result is 5. 
Result so far: 12218.5
Deduct 500 from 510 and we're left 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.

Step 9:
100 can be fit into 100 1 times, resulting in a remainder of 0.
The number 1 becomes the next digit in our result. 
Result so far: 12218.51
If we subtract 100 from 100, we get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 10:
0 divided by 100 is 0 with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 12218.51
If we subtract 0 from 0, we get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Going ahead to step 11:
100 goes into 0 0 times with a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 12218.51
Subtracting 0 from 0 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The final outcome is 12218.51, with a leftover of 0.0.