78521 ÷ 51 
Let's see how many times 51 fits into 78521.

Going ahead to step 1:
51 can be fit into 7 0 times, resulting in a remainder of 7.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 7 and we're left with 7.
Append the next digit (8) from the dividend to 7 and continue with: 78 / 51

Going ahead to step 2:
51 goes into 78 1 times with a remainder of 27.
Write down 1 as next digit of the result. 
Result so far: 1.0
Subtract 51 from 78 to get 27.
Grab the next digit (5) from the dividend, add it to 27, then carry on: 275 / 51

Going ahead to step 3:
275 divided by 51 is 5 with a remainder of 20.
The number 5 becomes the next digit in our result. 
Result so far: 15.0
Subtract 255 from 275 to get 20.
Append the next digit (2) from the dividend to 20 and continue with: 202 / 51

On to step 4:
If we divide 202 by 51, we get 3 and a remainder of 49.
Put 3 as the next digit of the answer. 
Result so far: 153.0
Subtract 153 from 202 to get 49.
Append the next digit (1) from the dividend to 49 and continue with: 491 / 51

Let's proceed to step 5:
491 divided by 51 is 9 with a remainder of 32.
The next digit of our result is 9. 
Result so far: 1539.0
Subtract 459 from 491 to get 32.
Since there are no more digits in the dividend, we add a zero to the remainder making it 320, and continue the process.

Going ahead to step 6:
If we divide 320 by 51, we get 6 and a remainder of 14.
Use 6 as the next digit of our solution. 
Result so far: 1539.6
If we subtract 306 from 320, we get 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Going ahead to step 7:
51 can be fit into 140 2 times, resulting in a remainder of 38.
Put 2 as the next digit of the answer. 
Result so far: 1539.62
Deduct 102 from 140 and we're left with 38.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

Advancing to step 8:
If we divide 380 by 51, we get 7 and a remainder of 23.
The number 7 becomes the next digit in our result. 
Result so far: 1539.627
The remainder is 23 after subtracting 357 from 380.
Since there are no more digits in the dividend, we add a zero to the remainder making it 230, and continue the process.

Moving on to step 9:
51 can be fit into 230 4 times, resulting in a remainder of 26.
The next digit of our result is 4. 
Result so far: 1539.6274
If we take 204 away from 230, we end up with 26.
Since there are no more digits in the dividend, we add a zero to the remainder making it 260, and continue the process.

Step 10:
51 goes into 260 5 times with a remainder of 5.
Use 5 as the next digit of our solution. 
Result so far: 1539.62745
The remainder is 5 after subtracting 255 from 260.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Going ahead to step 11:
If we divide 50 by 51, we get 0 and a remainder of 50.
Write down 0 as next digit of the result. 
Result so far: 1539.62745
Subtracting 0 from 50 leaves us with 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Going ahead to step 12:
If we divide 500 by 51, we get 9 and a remainder of 41.
The next digit of our result is 9. 
Result so far: 1539.6274509
If we subtract 459 from 500, we get 41.
Since there are no more digits in the dividend, we add a zero to the remainder making it 410, and continue the process.

Step 13:
51 goes into 410 8 times with a remainder of 2.
The number 8 becomes the next digit in our result. 
Result so far: 1539.62745098
Subtract 408 from 410 to get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

After the division, we end up with 1539.62745098 and a remainder of 2e-09.