121855 divided by 39 
Let's see how many times 39 fits into 121855.

Going ahead to step 1:
The number 39 fits into 1 0 times, leaving a remainder of 1.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 1, we end up with 1.
Take the next digit (2) from the dividend and append it to 1, then repeat: 12 / 39

Advancing to step 2:
12 divided by 39 is 0 with a remainder of 12.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 12 after subtracting 0 from 12.
Include the next digit (1) from the dividend after 12, then repeat: 121 / 39

Advancing to step 3:
121 divided by 39 is 3 with a remainder of 4.
The next digit of our result is 3. 
Result so far: 3.0
Subtracting 117 from 121 leaves us with 4.
Grab the next digit (8) from the dividend, add it to 4, then carry on: 48 / 39

Going ahead to step 4:
When dividing 48 by 39, we get 1 with a remainder of 9.
Use 1 as the next digit of our solution. 
Result so far: 31.0
If we take 39 away from 48, we end up with 9.
Fetch the next digit (5) from the dividend, attach it to 9 and continue: 95 / 39

Advancing to step 5:
39 goes into 95 2 times with a remainder of 17.
Write down 2 as next digit of the result. 
Result so far: 312.0
Deduct 78 from 95 and we're left with 17.
Take the next digit (5) from the dividend and append it to 17, then repeat: 175 / 39

Step 6:
175 divided by 39 is 4 with a remainder of 19.
Use 4 as the next digit of our solution. 
Result so far: 3124.0
The remainder is 19 after subtracting 156 from 175.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Let's proceed to step 7:
When dividing 190 by 39, we get 4 with a remainder of 34.
Write down 4 as next digit of the result. 
Result so far: 3124.4
If we subtract 156 from 190, we get 34.
Since there are no more digits in the dividend, we add a zero to the remainder making it 340, and continue the process.

On to step 8:
340 divided by 39 is 8 with a remainder of 28.
Record the quotient 8 as the next digit in the result. 
Result so far: 3124.48
If we take 312 away from 340, we end up with 28.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

On to step 9:
If we divide 280 by 39, we get 7 and a remainder of 7.
The next digit of our result is 7. 
Result so far: 3124.487
Subtracting 273 from 280 leaves us 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.

Advancing to step 10:
39 can be fit into 70 1 times, resulting in a remainder of 31.
The next digit of our result is 1. 
Result so far: 3124.4871
The remainder is 31 after subtracting 39 from 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 310, and continue the process.

Going ahead to step 11:
The number 39 fits into 310 7 times, leaving a remainder of 37.
Write down 7 as next digit of the result. 
Result so far: 3124.48717
The remainder is 37 after subtracting 273 from 310.
Since there are no more digits in the dividend, we add a zero to the remainder making it 370, and continue the process.

Advancing to step 12:
39 can be fit into 370 9 times, resulting in a remainder of 19.
The next digit of our result is 9. 
Result so far: 3124.487179
Deduct 351 from 370 and we're left with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Going ahead to step 13:
The number 39 fits into 190 4 times, leaving a remainder of 34.
Write down 4 as next digit of the result. 
Result so far: 3124.4871794
If we subtract 156 from 190, we get 34.
Since there are no more digits in the dividend, we add a zero to the remainder making it 340, and continue the process.

Moving on to step 14:
39 can be fit into 340 8 times, resulting in a remainder of 28.
The number 8 becomes the next digit in our result. 
Result so far: 3124.48717948
Subtract 312 from 340 to get 28.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

The final outcome is 3124.48717948, with a leftover of 2.8e-08.