21515232 ÷ 904 
Our goal is to divide 21515232 by 904.

Step 1:
2 divided by 904 is 0 with a remainder of 2.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 2 and we're left with 2.
Append the next digit (1) from the dividend to 2 and continue with: 21 / 904

Going ahead to step 2:
The number 904 fits into 21 0 times, leaving a remainder of 21.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 21 leaves us with 21.
Append the next digit (5) from the dividend to 21 and continue with: 215 / 904

On to step 3:
215 divided by 904 is 0 with a remainder of 215.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 215, we get 215.
Append the next digit (1) from the dividend to 215 and continue with: 2151 / 904

Advancing to step 4:
When dividing 2151 by 904, we get 2 with a remainder of 343.
The next digit of our result is 2. 
Result so far: 2.0
If we subtract 1808 from 2151, we get 343.
Bring next digit (5) of the dividend behind the 343 and repeat the process: 3435 / 904

Moving on to step 5:
3435 divided by 904 is 3 with a remainder of 723.
Write down 3 as next digit of the result. 
Result so far: 23.0
If we subtract 2712 from 3435, we get 723.
Include the next digit (2) from the dividend after 723, then repeat: 7232 / 904

Going ahead to step 6:
If we divide 7232 by 904, we get 8 and a remainder of 0.
Use 8 as the next digit of our solution. 
Result so far: 238.0
Deduct 7232 from 7232 and we're left with 0.
Append the next digit (3) from the dividend to 0 and continue with: 3 / 904

Advancing to step 7:
When dividing 3 by 904, we get 0 with a remainder of 3.
Write down 0 as next digit of the result. 
Result so far: 2380.0
Deduct 0 from 3 and we're left with 3.
Take the next digit (2) from the dividend and append it to 3, then repeat: 32 / 904

Moving on to step 8:
904 can be fit into 32 0 times, resulting in a remainder of 32.
Record the quotient 0 as the next digit in the result. 
Result so far: 23800.0
Subtracting 0 from 32 leaves us with 32.
Since there are no more digits in the dividend, we add a zero to the remainder making it 320, and continue the process.

Moving on to step 9:
904 can be fit into 320 0 times, resulting in a remainder of 320.
The next digit of our result is 0. 
Result so far: 23800.0
Subtracting 0 from 320 leaves us with 320.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3200, and continue the process.

On to step 10:
904 goes into 3200 3 times with a remainder of 488.
The number 3 becomes the next digit in our result. 
Result so far: 23800.03
Subtract 2712 from 3200 to get 488.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4880, and continue the process.

Step 11:
If we divide 4880 by 904, we get 5 and a remainder of 360.
Put 5 as the next digit of the answer. 
Result so far: 23800.035
Subtract 4520 from 4880 to get 360.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3600, and continue the process.

On to step 12:
904 can be fit into 3600 3 times, resulting in a remainder of 888.
Put 3 as the next digit of the answer. 
Result so far: 23800.0353
Deduct 2712 from 3600 and we're left with 888.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8880, and continue the process.

Step 13:
If we divide 8880 by 904, we get 9 and a remainder of 744.
The next digit of our result is 9. 
Result so far: 23800.03539
If we take 8136 away from 8880, we end up with 744.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7440, and continue the process.

Moving on to step 14:
904 goes into 7440 8 times with a remainder of 208.
The next digit of our result is 8. 
Result so far: 23800.035398
Deduct 7232 from 7440 and we're left with 208.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2080, and continue the process.

Advancing to step 15:
2080 divided by 904 is 2 with a remainder of 272.
Use 2 as the next digit of our solution. 
Result so far: 23800.0353982
Deduct 1808 from 2080 and we're left with 272.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2720, and continue the process.

Going ahead to step 16:
If we divide 2720 by 904, we get 3 and a remainder of 8.
Put 3 as the next digit of the answer. 
Result so far: 23800.03539823
If we take 2712 away from 2720, we end up with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

After the division, we end up with 23800.03539823 and a remainder of 8e-09.