91854478 divided by 646 
We want to figure out the number of times 91854478 can be divided by 646.

Moving on to step 1:
646 goes into 9 0 times with a remainder of 9.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 9 leaves us with 9.
Include the next digit (1) from the dividend after 9, then repeat: 91 / 646

Moving on to step 2:
If we divide 91 by 646, we get 0 and a remainder of 91.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 91 after subtracting 0 from 91.
Grab the next digit (8) from the dividend, add it to 91, then carry on: 918 / 646

Advancing to step 3:
The number 646 fits into 918 1 times, leaving a remainder of 272.
Put 1 as the next digit of the answer. 
Result so far: 1.0
Subtract 646 from 918 to get 272.
Fetch the next digit (5) from the dividend, attach it to 272 and continue: 2725 / 646

Step 4:
When dividing 2725 by 646, we get 4 with a remainder of 141.
Put 4 as the next digit of the answer. 
Result so far: 14.0
Subtracting 2584 from 2725 leaves us with 141.
Bring next digit (4) of the dividend behind the 141 and repeat the process: 1414 / 646

Going ahead to step 5:
If we divide 1414 by 646, we get 2 and a remainder of 122.
The number 2 becomes the next digit in our result. 
Result so far: 142.0
If we take 1292 away from 1414, we end up with 122.
Grab the next digit (4) from the dividend, add it to 122, then carry on: 1224 / 646

Step 6:
646 can be fit into 1224 1 times, resulting in a remainder of 578.
Write down 1 as next digit of the result. 
Result so far: 1421.0
If we subtract 646 from 1224, we get 578.
Grab the next digit (7) from the dividend, add it to 578, then carry on: 5787 / 646

Moving on to step 7:
646 goes into 5787 8 times with a remainder of 619.
Use 8 as the next digit of our solution. 
Result so far: 14218.0
Deduct 5168 from 5787 and we're left with 619.
Append the next digit (8) from the dividend to 619 and continue with: 6198 / 646

Let's proceed to step 8:
When dividing 6198 by 646, we get 9 with a remainder of 384.
The number 9 becomes the next digit in our result. 
Result so far: 142189.0
Subtracting 5814 from 6198 leaves us with 384.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3840, and continue the process.

Moving on to step 9:
646 goes into 3840 5 times with a remainder of 610.
Use 5 as the next digit of our solution. 
Result so far: 142189.5
If we subtract 3230 from 3840, we get 610.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6100, and continue the process.

Advancing to step 10:
The number 646 fits into 6100 9 times, leaving a remainder of 286.
Record the quotient 9 as the next digit in the result. 
Result so far: 142189.59
If we subtract 5814 from 6100, we get 286.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2860, and continue the process.

On to step 11:
646 can be fit into 2860 4 times, resulting in a remainder of 276.
Write down 4 as next digit of the result. 
Result so far: 142189.594
Subtract 2584 from 2860 to get 276.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2760, and continue the process.

Advancing to step 12:
2760 divided by 646 is 4 with a remainder of 176.
The number 4 becomes the next digit in our result. 
Result so far: 142189.5944
If we take 2584 away from 2760, we end up with 176.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1760, and continue the process.

The final result is 142189.5944 with a remainder of 0.00176.