We're dividing 371937 by 3 
The aim is to understand the frequency of 3 in 371937.

Advancing to step 1:
The number 3 fits into 3 1 times, leaving a remainder of 0.
Write down 1 as next digit of the result. 
Result so far: 1.0
Subtracting 3 from 3 leaves us with 0.
Fetch the next digit (7) from the dividend, attach it to 0 and continue: 7 / 3

Going ahead to step 2:
3 goes into 7 2 times with a remainder of 1.
Use 2 as the next digit of our solution. 
Result so far: 12.0
If we subtract 6 from 7, we get 1.
Take the next digit (1) from the dividend and append it to 1, then repeat: 11 / 3

On to step 3:
11 divided by 3 is 3 with a remainder of 2.
Put 3 as the next digit of the answer. 
Result so far: 123.0
Subtract 9 from 11 to get 2.
Take the next digit (9) from the dividend and append it to 2, then repeat: 29 / 3

Step 4:
3 goes into 29 9 times with a remainder of 2.
Put 9 as the next digit of the answer. 
Result so far: 1239.0
The remainder is 2 after subtracting 27 from 29.
Take the next digit (3) from the dividend and append it to 2, then repeat: 23 / 3

Going ahead to step 5:
If we divide 23 by 3, we get 7 and a remainder of 2.
Write down 7 as next digit of the result. 
Result so far: 12397.0
Deduct 21 from 23 and we're left with 2.
Take the next digit (7) from the dividend and append it to 2, then repeat: 27 / 3

Moving on to step 6:
3 can be fit into 27 9 times, resulting in a remainder of 0.
The next digit of our result is 9. 
Result so far: 123979.0
Subtracting 27 from 27 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 7:
0 divided by 3 is 0 with a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 123979.0
The remainder is 0 after subtracting 0 from 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

On to step 8:
When dividing 0 by 3, we get 0 with a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 123979.0
If we subtract 0 from 0, we get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The final result is 123979.0 with a remainder of 0.0.