78396817 divided by 646 
We're looking to find how many times 646 goes into 78396817.

Step 1:
The number 646 fits into 7 0 times, leaving a remainder of 7.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 7 after subtracting 0 from 7.
Grab the next digit (8) from the dividend, add it to 7, then carry on: 78 / 646

Step 2:
When dividing 78 by 646, we get 0 with a remainder of 78.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 78 and we're left with 78.
Append the next digit (3) from the dividend to 78 and continue with: 783 / 646

Let's proceed to step 3:
646 can be fit into 783 1 times, resulting in a remainder of 137.
Write down 1 as next digit of the result. 
Result so far: 1.0
Deduct 646 from 783 and we're left with 137.
Include the next digit (9) from the dividend after 137, then repeat: 1379 / 646

Let's proceed to step 4:
646 can be fit into 1379 2 times, resulting in a remainder of 87.
Use 2 as the next digit of our solution. 
Result so far: 12.0
Deduct 1292 from 1379 and we're left with 87.
Take the next digit (6) from the dividend and append it to 87, then repeat: 876 / 646

Moving on to step 5:
When dividing 876 by 646, we get 1 with a remainder of 230.
Use 1 as the next digit of our solution. 
Result so far: 121.0
The remainder is 230 after subtracting 646 from 876.
Bring next digit (8) of the dividend behind the 230 and repeat the process: 2308 / 646

Going ahead to step 6:
If we divide 2308 by 646, we get 3 and a remainder of 370.
Use 3 as the next digit of our solution. 
Result so far: 1213.0
Deduct 1938 from 2308 and we're left with 370.
Take the next digit (1) from the dividend and append it to 370, then repeat: 3701 / 646

Advancing to step 7:
646 goes into 3701 5 times with a remainder of 471.
The number 5 becomes the next digit in our result. 
Result so far: 12135.0
Deduct 3230 from 3701 and we're left with 471.
Take the next digit (7) from the dividend and append it to 471, then repeat: 4717 / 646

Moving on to step 8:
4717 divided by 646 is 7 with a remainder of 195.
The number 7 becomes the next digit in our result. 
Result so far: 121357.0
Subtract 4522 from 4717 to get 195.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1950, and continue the process.

Moving on to step 9:
The number 646 fits into 1950 3 times, leaving a remainder of 12.
Put 3 as the next digit of the answer. 
Result so far: 121357.3
If we subtract 1938 from 1950, we get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

On to step 10:
If we divide 120 by 646, we get 0 and a remainder of 120.
The next digit of our result is 0. 
Result so far: 121357.3
Deduct 0 from 120 and we're left with 120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1200, and continue the process.

Going ahead to step 11:
If we divide 1200 by 646, we get 1 and a remainder of 554.
Write down 1 as next digit of the result. 
Result so far: 121357.301
Deduct 646 from 1200 and we're left with 554.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5540, and continue the process.

Step 12:
The number 646 fits into 5540 8 times, leaving a remainder of 372.
Write down 8 as next digit of the result. 
Result so far: 121357.3018
The remainder is 372 after subtracting 5168 from 5540.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3720, and continue the process.

Moving on to step 13:
The number 646 fits into 3720 5 times, leaving a remainder of 490.
Record the quotient 5 as the next digit in the result. 
Result so far: 121357.30185
If we subtract 3230 from 3720, we get 490.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4900, and continue the process.

Step 14:
When dividing 4900 by 646, we get 7 with a remainder of 378.
The next digit of our result is 7. 
Result so far: 121357.301857
If we take 4522 away from 4900, we end up with 378.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3780, and continue the process.

Let's proceed to step 15:
646 can be fit into 3780 5 times, resulting in a remainder of 550.
The number 5 becomes the next digit in our result. 
Result so far: 121357.3018575
The remainder is 550 after subtracting 3230 from 3780.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5500, and continue the process.

Advancing to step 16:
When dividing 5500 by 646, we get 8 with a remainder of 332.
Write down 8 as next digit of the result. 
Result so far: 121357.30185758
Subtract 5168 from 5500 to get 332.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3320, and continue the process.

The final outcome is 121357.30185758, with a leftover of 3.32e-07.