81638152 divided by 646 
Let's see how many times 646 fits into 81638152.

Going ahead to step 1:
If we divide 8 by 646, we get 0 and a remainder of 8.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 8 and we're left with 8.
Bring next digit (1) of the dividend behind the 8 and repeat the process: 81 / 646

Advancing to step 2:
646 can be fit into 81 0 times, resulting in a remainder of 81.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 81 leaves us with 81.
Take the next digit (6) from the dividend and append it to 81, then repeat: 816 / 646

On to step 3:
646 goes into 816 1 times with a remainder of 170.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
Subtracting 646 from 816 leaves us with 170.
Take the next digit (3) from the dividend and append it to 170, then repeat: 1703 / 646

On to step 4:
646 can be fit into 1703 2 times, resulting in a remainder of 411.
The next digit of our result is 2. 
Result so far: 12.0
Subtracting 1292 from 1703 leaves us with 411.
Append the next digit (8) from the dividend to 411 and continue with: 4118 / 646

Going ahead to step 5:
4118 divided by 646 is 6 with a remainder of 242.
Put 6 as the next digit of the answer. 
Result so far: 126.0
If we take 3876 away from 4118, we end up with 242.
Append the next digit (1) from the dividend to 242 and continue with: 2421 / 646

Going ahead to step 6:
646 goes into 2421 3 times with a remainder of 483.
Use 3 as the next digit of our solution. 
Result so far: 1263.0
Subtracting 1938 from 2421 leaves us with 483.
Fetch the next digit (5) from the dividend, attach it to 483 and continue: 4835 / 646

On to step 7:
4835 divided by 646 is 7 with a remainder of 313.
Put 7 as the next digit of the answer. 
Result so far: 12637.0
The remainder is 313 after subtracting 4522 from 4835.
Fetch the next digit (2) from the dividend, attach it to 313 and continue: 3132 / 646

Moving on to step 8:
646 can be fit into 3132 4 times, resulting in a remainder of 548.
Write down 4 as next digit of the result. 
Result so far: 126374.0
Subtract 2584 from 3132 to get 548.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5480, and continue the process.

Step 9:
When dividing 5480 by 646, we get 8 with a remainder of 312.
Use 8 as the next digit of our solution. 
Result so far: 126374.8
If we take 5168 away from 5480, we end up with 312.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3120, and continue the process.

Step 10:
646 can be fit into 3120 4 times, resulting in a remainder of 536.
Put 4 as the next digit of the answer. 
Result so far: 126374.84
Subtracting 2584 from 3120 leaves us with 536.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5360, and continue the process.

Let's proceed to step 11:
646 goes into 5360 8 times with a remainder of 192.
Record the quotient 8 as the next digit in the result. 
Result so far: 126374.848
Deduct 5168 from 5360 and we're left with 192.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1920, and continue the process.

Advancing to step 12:
646 can be fit into 1920 2 times, resulting in a remainder of 628.
The next digit of our result is 2. 
Result so far: 126374.8482
The remainder is 628 after subtracting 1292 from 1920.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6280, and continue the process.

Going ahead to step 13:
6280 divided by 646 is 9 with a remainder of 466.
Put 9 as the next digit of the answer. 
Result so far: 126374.84829
If we subtract 5814 from 6280, we get 466.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4660, and continue the process.

On to step 14:
The number 646 fits into 4660 7 times, leaving a remainder of 138.
The next digit of our result is 7. 
Result so far: 126374.848297
If we subtract 4522 from 4660, we get 138.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1380, and continue the process.

Step 15:
When dividing 1380 by 646, we get 2 with a remainder of 88.
Put 2 as the next digit of the answer. 
Result so far: 126374.8482972
Deduct 1292 from 1380 and we're left with 88.
Since there are no more digits in the dividend, we add a zero to the remainder making it 880, and continue the process.

Going ahead to step 16:
646 goes into 880 1 times with a remainder of 234.
The number 1 becomes the next digit in our result. 
Result so far: 126374.84829721
Deduct 646 from 880 and we're left with 234.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2340, and continue the process.

The final result is 126374.84829721 with a remainder of 2.34e-07.