Let's divide 78021557 by 840
We want to figure out the number of times 78021557 can be divided by 840.

Advancing to step 1:
840 can be fit into 7 0 times, resulting in a remainder of 7.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 7 leaves us with 7.
Fetch the next digit (8) from the dividend, attach it to 7 and continue: 78 / 840

Advancing to step 2:
78 divided by 840 is 0 with a remainder of 78.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 78 leaves us with 78.
Grab the next digit (0) from the dividend, add it to 78, then carry on: 780 / 840

Let's proceed to step 3:
780 divided by 840 is 0 with a remainder of 780.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 780 leaves us with 780.
Bring next digit (2) of the dividend behind the 780 and repeat the process: 7802 / 840

Step 4:
The number 840 fits into 7802 9 times, leaving a remainder of 242.
Put 9 as the next digit of the answer. 
Result so far: 9.0
If we subtract 7560 from 7802, we get 242.
Append the next digit (1) from the dividend to 242 and continue with: 2421 / 840

On to step 5:
840 goes into 2421 2 times with a remainder of 741.
Use 2 as the next digit of our solution. 
Result so far: 92.0
Subtract 1680 from 2421 to get 741.
Bring next digit (5) of the dividend behind the 741 and repeat the process: 7415 / 840

Step 6:
7415 divided by 840 is 8 with a remainder of 695.
Write down 8 as next digit of the result. 
Result so far: 928.0
If we subtract 6720 from 7415, we get 695.
Include the next digit (5) from the dividend after 695, then repeat: 6955 / 840

Moving on to step 7:
6955 divided by 840 is 8 with a remainder of 235.
Write down 8 as next digit of the result. 
Result so far: 9288.0
If we take 6720 away from 6955, we end up with 235.
Take the next digit (7) from the dividend and append it to 235, then repeat: 2357 / 840

Going ahead to step 8:
2357 divided by 840 is 2 with a remainder of 677.
Put 2 as the next digit of the answer. 
Result so far: 92882.0
Deduct 1680 from 2357 and we're left with 677.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6770, and continue the process.

On to step 9:
The number 840 fits into 6770 8 times, leaving a remainder of 50.
Use 8 as the next digit of our solution. 
Result so far: 92882.8
If we subtract 6720 from 6770, we get 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Step 10:
The number 840 fits into 500 0 times, leaving a remainder of 500.
Record the quotient 0 as the next digit in the result. 
Result so far: 92882.8
If we subtract 0 from 500, we get 500.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5000, and continue the process.

Going ahead to step 11:
840 goes into 5000 5 times with a remainder of 800.
Use 5 as the next digit of our solution. 
Result so far: 92882.805
The remainder is 800 after subtracting 4200 from 5000.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8000, and continue the process.

On to step 12:
The number 840 fits into 8000 9 times, leaving a remainder of 440.
The next digit of our result is 9. 
Result so far: 92882.8059
Deduct 7560 from 8000 and we're left with 440.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4400, and continue the process.

Step 13:
840 goes into 4400 5 times with a remainder of 200.
The next digit of our result is 5. 
Result so far: 92882.80595
Deduct 4200 from 4400 and we're left with 200.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2000, and continue the process.

On to step 14:
840 goes into 2000 2 times with a remainder of 320.
Write down 2 as next digit of the result. 
Result so far: 92882.805952
The remainder is 320 after subtracting 1680 from 2000.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3200, and continue the process.

Going ahead to step 15:
840 goes into 3200 3 times with a remainder of 680.
Write down 3 as next digit of the result. 
Result so far: 92882.8059523
Subtracting 2520 from 3200 leaves us with 680.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6800, and continue the process.

Advancing to step 16:
840 goes into 6800 8 times with a remainder of 80.
Put 8 as the next digit of the answer. 
Result so far: 92882.80595238
If we take 6720 away from 6800, we end up with 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 800, and continue the process.

After the division, we end up with 92882.80595238 and a remainder of 8e-08.