66717950 divided by 646 
We want to figure out the number of times 66717950 can be divided by 646.

Step 1:
If we divide 6 by 646, we get 0 and a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 6 and we're left with 6.
Fetch the next digit (6) from the dividend, attach it to 6 and continue: 66 / 646

Advancing to step 2:
646 can be fit into 66 0 times, resulting in a remainder of 66.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 66 and we're left with 66.
Take the next digit (7) from the dividend and append it to 66, then repeat: 667 / 646

On to step 3:
667 divided by 646 is 1 with a remainder of 21.
Use 1 as the next digit of our solution. 
Result so far: 1.0
The remainder is 21 after subtracting 646 from 667.
Bring next digit (1) of the dividend behind the 21 and repeat the process: 211 / 646

Going ahead to step 4:
646 goes into 211 0 times with a remainder of 211.
The number 0 becomes the next digit in our result. 
Result so far: 10.0
If we take 0 away from 211, we end up with 211.
Grab the next digit (7) from the dividend, add it to 211, then carry on: 2117 / 646

On to step 5:
If we divide 2117 by 646, we get 3 and a remainder of 179.
Put 3 as the next digit of the answer. 
Result so far: 103.0
If we take 1938 away from 2117, we end up with 179.
Fetch the next digit (9) from the dividend, attach it to 179 and continue: 1799 / 646

Let's proceed to step 6:
1799 divided by 646 is 2 with a remainder of 507.
The number 2 becomes the next digit in our result. 
Result so far: 1032.0
If we subtract 1292 from 1799, we get 507.
Take the next digit (5) from the dividend and append it to 507, then repeat: 5075 / 646

Let's proceed to step 7:
646 goes into 5075 7 times with a remainder of 553.
Write down 7 as next digit of the result. 
Result so far: 10327.0
If we take 4522 away from 5075, we end up with 553.
Take the next digit (0) from the dividend and append it to 553, then repeat: 5530 / 646

Going ahead to step 8:
646 can be fit into 5530 8 times, resulting in a remainder of 362.
Write down 8 as next digit of the result. 
Result so far: 103278.0
Subtract 5168 from 5530 to get 362.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3620, and continue the process.

Let's proceed to step 9:
When dividing 3620 by 646, we get 5 with a remainder of 390.
Use 5 as the next digit of our solution. 
Result so far: 103278.5
Subtracting 3230 from 3620 leaves us with 390.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3900, and continue the process.

Step 10:
646 goes into 3900 6 times with a remainder of 24.
Record the quotient 6 as the next digit in the result. 
Result so far: 103278.56
If we take 3876 away from 3900, we end up with 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

On to step 11:
The number 646 fits into 240 0 times, leaving a remainder of 240.
The number 0 becomes the next digit in our result. 
Result so far: 103278.56
If we subtract 0 from 240, we get 240.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2400, and continue the process.

Let's proceed to step 12:
If we divide 2400 by 646, we get 3 and a remainder of 462.
Use 3 as the next digit of our solution. 
Result so far: 103278.5603
Deduct 1938 from 2400 and we're left with 462.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4620, and continue the process.

Going ahead to step 13:
The number 646 fits into 4620 7 times, leaving a remainder of 98.
The next digit of our result is 7. 
Result so far: 103278.56037
Deduct 4522 from 4620 and we're left with 98.
Since there are no more digits in the dividend, we add a zero to the remainder making it 980, and continue the process.

On to step 14:
646 can be fit into 980 1 times, resulting in a remainder of 334.
The number 1 becomes the next digit in our result. 
Result so far: 103278.560371
If we subtract 646 from 980, we get 334.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3340, and continue the process.

Moving on to step 15:
When dividing 3340 by 646, we get 5 with a remainder of 110.
Put 5 as the next digit of the answer. 
Result so far: 103278.5603715
Subtract 3230 from 3340 to get 110.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1100, and continue the process.

On to step 16:
646 goes into 1100 1 times with a remainder of 454.
Record the quotient 1 as the next digit in the result. 
Result so far: 103278.56037151
If we take 646 away from 1100, we end up with 454.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4540, and continue the process.

After the division, we end up with 103278.56037151 and a remainder of 4.54e-07.