3871885 ÷ 300 
Let's see how many times 300 fits into 3871885.

Going ahead to step 1:
When dividing 3 by 300, we get 0 with a remainder of 3.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 3, we get 3.
Fetch the next digit (8) from the dividend, attach it to 3 and continue: 38 / 300

Advancing to step 2:
38 divided by 300 is 0 with a remainder of 38.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 38 after subtracting 0 from 38.
Bring next digit (7) of the dividend behind the 38 and repeat the process: 387 / 300

On to step 3:
387 divided by 300 is 1 with a remainder of 87.
Put 1 as the next digit of the answer. 
Result so far: 1.0
Deduct 300 from 387 and we're left with 87.
Bring next digit (1) of the dividend behind the 87 and repeat the process: 871 / 300

Moving on to step 4:
871 divided by 300 is 2 with a remainder of 271.
Put 2 as the next digit of the answer. 
Result so far: 12.0
Subtracting 600 from 871 leaves us with 271.
Bring next digit (8) of the dividend behind the 271 and repeat the process: 2718 / 300

On to step 5:
300 can be fit into 2718 9 times, resulting in a remainder of 18.
Record the quotient 9 as the next digit in the result. 
Result so far: 129.0
Subtract 2700 from 2718 to get 18.
Take the next digit (8) from the dividend and append it to 18, then repeat: 188 / 300

On to step 6:
188 divided by 300 is 0 with a remainder of 188.
Record the quotient 0 as the next digit in the result. 
Result so far: 1290.0
Subtracting 0 from 188 leaves us with 188.
Take the next digit (5) from the dividend and append it to 188, then repeat: 1885 / 300

Advancing to step 7:
When dividing 1885 by 300, we get 6 with a remainder of 85.
Use 6 as the next digit of our solution. 
Result so far: 12906.0
Subtracting 1800 from 1885 leaves us with 85.
Since there are no more digits in the dividend, we add a zero to the remainder making it 850, and continue the process.

Going ahead to step 8:
850 divided by 300 is 2 with a remainder of 250.
Write down 2 as next digit of the result. 
Result so far: 12906.2
Subtracting 600 from 850 leaves us with 250.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2500, and continue the process.

Advancing to step 9:
The number 300 fits into 2500 8 times, leaving a remainder of 100.
Record the quotient 8 as the next digit in the result. 
Result so far: 12906.28
If we take 2400 away from 2500, we end up with 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1000, and continue the process.

Moving on to step 10:
300 goes into 1000 3 times with a remainder of 100.
Use 3 as the next digit of our solution. 
Result so far: 12906.283
Subtract 900 from 1000 to get 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1000, and continue the process.

Moving on to step 11:
When dividing 1000 by 300, we get 3 with a remainder of 100.
The number 3 becomes the next digit in our result. 
Result so far: 12906.2833
Subtracting 900 from 1000 leaves us with 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1000, and continue the process.

The final outcome is 12906.2833, with a leftover of 0.001.