643639 ÷ 53 
Our goal is to divide 643639 by 53.

Going ahead to step 1:
6 divided by 53 is 0 with a remainder of 6.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 6 after subtracting 0 from 6.
Include the next digit (4) from the dividend after 6, then repeat: 64 / 53

Moving on to step 2:
53 can be fit into 64 1 times, resulting in a remainder of 11.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
Subtract 53 from 64 to get 11.
Take the next digit (3) from the dividend and append it to 11, then repeat: 113 / 53

Step 3:
53 can be fit into 113 2 times, resulting in a remainder of 7.
Write down 2 as next digit of the result. 
Result so far: 12.0
Subtract 106 from 113 to get 7.
Bring next digit (6) of the dividend behind the 7 and repeat the process: 76 / 53

Going ahead to step 4:
When dividing 76 by 53, we get 1 with a remainder of 23.
Put 1 as the next digit of the answer. 
Result so far: 121.0
If we subtract 53 from 76, we get 23.
Grab the next digit (3) from the dividend, add it to 23, then carry on: 233 / 53

Step 5:
233 divided by 53 is 4 with a remainder of 21.
The number 4 becomes the next digit in our result. 
Result so far: 1214.0
If we take 212 away from 233, we end up with 21.
Grab the next digit (9) from the dividend, add it to 21, then carry on: 219 / 53

Step 6:
If we divide 219 by 53, we get 4 and a remainder of 7.
Write down 4 as next digit of the result. 
Result so far: 12144.0
Deduct 212 from 219 and we're left with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Let's proceed to step 7:
53 goes into 70 1 times with a remainder of 17.
The number 1 becomes the next digit in our result. 
Result so far: 12144.1
Subtract 53 from 70 to get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Going ahead to step 8:
53 goes into 170 3 times with a remainder of 11.
Put 3 as the next digit of the answer. 
Result so far: 12144.13
Deduct 159 from 170 and we're left with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Going ahead to step 9:
53 can be fit into 110 2 times, resulting in a remainder of 4.
Record the quotient 2 as the next digit in the result. 
Result so far: 12144.132
If we take 106 away from 110, we end up with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Advancing to step 10:
When dividing 40 by 53, we get 0 with a remainder of 40.
The next digit of our result is 0. 
Result so far: 12144.132
The remainder is 40 after subtracting 0 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Going ahead to step 11:
400 divided by 53 is 7 with a remainder of 29.
Record the quotient 7 as the next digit in the result. 
Result so far: 12144.13207
If we subtract 371 from 400, we get 29.
Since there are no more digits in the dividend, we add a zero to the remainder making it 290, and continue the process.

Step 12:
The number 53 fits into 290 5 times, leaving a remainder of 25.
Put 5 as the next digit of the answer. 
Result so far: 12144.132075
Subtracting 265 from 290 leaves us with 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

Step 13:
53 goes into 250 4 times with a remainder of 38.
The next digit of our result is 4. 
Result so far: 12144.1320754
The remainder is 38 after subtracting 212 from 250.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

On to step 14:
53 goes into 380 7 times with a remainder of 9.
The next digit of our result is 7. 
Result so far: 12144.13207547
If we subtract 371 from 380, we get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

The final outcome is 12144.13207547, with a leftover of 9e-09.