81221812 ÷ 225 
We want to figure out the number of times 81221812 can be divided by 225.

Advancing to step 1:
8 divided by 225 is 0 with a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 8, we end up with 8.
Fetch the next digit (1) from the dividend, attach it to 8 and continue: 81 / 225

Going ahead to step 2:
If we divide 81 by 225, we get 0 and a remainder of 81.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 81 leaves us with 81.
Grab the next digit (2) from the dividend, add it to 81, then carry on: 812 / 225

Step 3:
225 goes into 812 3 times with a remainder of 137.
Record the quotient 3 as the next digit in the result. 
Result so far: 3.0
Subtract 675 from 812 to get 137.
Take the next digit (2) from the dividend and append it to 137, then repeat: 1372 / 225

Going ahead to step 4:
225 can be fit into 1372 6 times, resulting in a remainder of 22.
Write down 6 as next digit of the result. 
Result so far: 36.0
Deduct 1350 from 1372 and we're left with 22.
Bring next digit (1) of the dividend behind the 22 and repeat the process: 221 / 225

On to step 5:
When dividing 221 by 225, we get 0 with a remainder of 221.
Record the quotient 0 as the next digit in the result. 
Result so far: 360.0
Subtracting 0 from 221 leaves us with 221.
Append the next digit (8) from the dividend to 221 and continue with: 2218 / 225

On to step 6:
The number 225 fits into 2218 9 times, leaving a remainder of 193.
Write down 9 as next digit of the result. 
Result so far: 3609.0
If we subtract 2025 from 2218, we get 193.
Bring next digit (1) of the dividend behind the 193 and repeat the process: 1931 / 225

Going ahead to step 7:
The number 225 fits into 1931 8 times, leaving a remainder of 131.
Put 8 as the next digit of the answer. 
Result so far: 36098.0
Subtracting 1800 from 1931 leaves us with 131.
Append the next digit (2) from the dividend to 131 and continue with: 1312 / 225

Step 8:
When dividing 1312 by 225, we get 5 with a remainder of 187.
Write down 5 as next digit of the result. 
Result so far: 360985.0
Subtracting 1125 from 1312 leaves us with 187.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1870, and continue the process.

Going ahead to step 9:
The number 225 fits into 1870 8 times, leaving a remainder of 70.
Record the quotient 8 as the next digit in the result. 
Result so far: 360985.8
Deduct 1800 from 1870 and we're left with 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

Going ahead to step 10:
The number 225 fits into 700 3 times, leaving a remainder of 25.
Write down 3 as next digit of the result. 
Result so far: 360985.83
If we take 675 away from 700, we end up with 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

Let's proceed to step 11:
250 divided by 225 is 1 with a remainder of 25.
The next digit of our result is 1. 
Result so far: 360985.831
Deduct 225 from 250 and we're left with 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

On to step 12:
If we divide 250 by 225, we get 1 and a remainder of 25.
Write down 1 as next digit of the result. 
Result so far: 360985.8311
Subtract 225 from 250 to get 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

In conclusion, the division gives 360985.8311 with a balance of 0.00025.