We look at the division of 121538 by 39 
We want to figure out the number of times 121538 can be divided by 39.

Step 1:
If we divide 1 by 39, we get 0 and a remainder of 1.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 1, we get 1.
Append the next digit (2) from the dividend to 1 and continue with: 12 / 39

Going ahead to step 2:
39 can be fit into 12 0 times, resulting in a remainder of 12.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 12 leaves us with 12.
Fetch the next digit (1) from the dividend, attach it to 12 and continue: 121 / 39

Let's proceed to step 3:
The number 39 fits into 121 3 times, leaving a remainder of 4.
Use 3 as the next digit of our solution. 
Result so far: 3.0
Deduct 117 from 121 and we're left with 4.
Bring next digit (5) of the dividend behind the 4 and repeat the process: 45 / 39

Advancing to step 4:
If we divide 45 by 39, we get 1 and a remainder of 6.
The next digit of our result is 1. 
Result so far: 31.0
Subtract 39 from 45 to get 6.
Grab the next digit (3) from the dividend, add it to 6, then carry on: 63 / 39

Going ahead to step 5:
The number 39 fits into 63 1 times, leaving a remainder of 24.
The next digit of our result is 1. 
Result so far: 311.0
Subtracting 39 from 63 leaves us with 24.
Include the next digit (8) from the dividend after 24, then repeat: 248 / 39

Advancing to step 6:
39 can be fit into 248 6 times, resulting in a remainder of 14.
The number 6 becomes the next digit in our result. 
Result so far: 3116.0
Subtracting 234 from 248 leaves us with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

On to step 7:
140 divided by 39 is 3 with a remainder of 23.
Write down 3 as next digit of the result. 
Result so far: 3116.3
If we subtract 117 from 140, we get 23.
Since there are no more digits in the dividend, we add a zero to the remainder making it 230, and continue the process.

Going ahead to step 8:
39 goes into 230 5 times with a remainder of 35.
Record the quotient 5 as the next digit in the result. 
Result so far: 3116.35
Subtracting 195 from 230 leaves us with 35.
Since there are no more digits in the dividend, we add a zero to the remainder making it 350, and continue the process.

On to step 9:
350 divided by 39 is 8 with a remainder of 38.
The next digit of our result is 8. 
Result so far: 3116.358
Deduct 312 from 350 and we're left with 38.
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 10:
380 divided by 39 is 9 with a remainder of 29.
Record the quotient 9 as the next digit in the result. 
Result so far: 3116.3589
If we subtract 351 from 380, 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.

Advancing to step 11:
39 can be fit into 290 7 times, resulting in a remainder of 17.
Put 7 as the next digit of the answer. 
Result so far: 3116.35897
Subtract 273 from 290 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.

Step 12:
170 divided by 39 is 4 with a remainder of 14.
The number 4 becomes the next digit in our result. 
Result so far: 3116.358974
Deduct 156 from 170 and we're left with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

On to step 13:
39 goes into 140 3 times with a remainder of 23.
The number 3 becomes the next digit in our result. 
Result so far: 3116.3589743
If we subtract 117 from 140, we get 23.
Since there are no more digits in the dividend, we add a zero to the remainder making it 230, and continue the process.

Going ahead to step 14:
230 divided by 39 is 5 with a remainder of 35.
The next digit of our result is 5. 
Result so far: 3116.35897435
Subtract 195 from 230 to get 35.
Since there are no more digits in the dividend, we add a zero to the remainder making it 350, and continue the process.

The final outcome is 3116.35897435, with a leftover of 3.5e-08.