We're dividing 7817428 by 643 
Our goal is to divide 7817428 by 643.

Going ahead to step 1:
When dividing 7 by 643, we get 0 with a remainder of 7.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 7 after subtracting 0 from 7.
Fetch the next digit (8) from the dividend, attach it to 7 and continue: 78 / 643

Moving on to step 2:
643 goes into 78 0 times with a remainder of 78.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 78 and we're left with 78.
Append the next digit (1) from the dividend to 78 and continue with: 781 / 643

Going ahead to step 3:
When dividing 781 by 643, we get 1 with a remainder of 138.
The next digit of our result is 1. 
Result so far: 1.0
If we subtract 643 from 781, we get 138.
Bring next digit (7) of the dividend behind the 138 and repeat the process: 1387 / 643

Step 4:
When dividing 1387 by 643, we get 2 with a remainder of 101.
Put 2 as the next digit of the answer. 
Result so far: 12.0
Subtract 1286 from 1387 to get 101.
Fetch the next digit (4) from the dividend, attach it to 101 and continue: 1014 / 643

Advancing to step 5:
If we divide 1014 by 643, we get 1 and a remainder of 371.
Put 1 as the next digit of the answer. 
Result so far: 121.0
Subtracting 643 from 1014 leaves us with 371.
Append the next digit (2) from the dividend to 371 and continue with: 3712 / 643

Moving on to step 6:
643 can be fit into 3712 5 times, resulting in a remainder of 497.
The number 5 becomes the next digit in our result. 
Result so far: 1215.0
If we subtract 3215 from 3712, we get 497.
Bring next digit (8) of the dividend behind the 497 and repeat the process: 4978 / 643

Going ahead to step 7:
4978 divided by 643 is 7 with a remainder of 477.
Write down 7 as next digit of the result. 
Result so far: 12157.0
Deduct 4501 from 4978 and we're left with 477.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4770, and continue the process.

Let's proceed to step 8:
If we divide 4770 by 643, we get 7 and a remainder of 269.
Put 7 as the next digit of the answer. 
Result so far: 12157.7
If we take 4501 away from 4770, we end up with 269.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2690, and continue the process.

On to step 9:
When dividing 2690 by 643, we get 4 with a remainder of 118.
The next digit of our result is 4. 
Result so far: 12157.74
Deduct 2572 from 2690 and we're left with 118.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1180, and continue the process.

On to step 10:
643 goes into 1180 1 times with a remainder of 537.
Record the quotient 1 as the next digit in the result. 
Result so far: 12157.741
Subtracting 643 from 1180 leaves us with 537.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5370, and continue the process.

Advancing to step 11:
The number 643 fits into 5370 8 times, leaving a remainder of 226.
Put 8 as the next digit of the answer. 
Result so far: 12157.7418
If we subtract 5144 from 5370, we get 226.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2260, and continue the process.

Advancing to step 12:
2260 divided by 643 is 3 with a remainder of 331.
The next digit of our result is 3. 
Result so far: 12157.74183
If we subtract 1929 from 2260, we get 331.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3310, and continue the process.

Going ahead to step 13:
643 goes into 3310 5 times with a remainder of 95.
Record the quotient 5 as the next digit in the result. 
Result so far: 12157.741835
Subtract 3215 from 3310 to get 95.
Since there are no more digits in the dividend, we add a zero to the remainder making it 950, and continue the process.

On to step 14:
643 goes into 950 1 times with a remainder of 307.
The next digit of our result is 1. 
Result so far: 12157.7418351
Deduct 643 from 950 and we're left with 307.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3070, and continue the process.

Let's proceed to step 15:
3070 divided by 643 is 4 with a remainder of 498.
Write down 4 as next digit of the result. 
Result so far: 12157.74183514
Subtracting 2572 from 3070 leaves us with 498.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4980, and continue the process.

The final outcome is 12157.74183514, with a leftover of 4.98e-07.