401209 ÷ 31 
Let's see how many times 31 fits into 401209.

Moving on to step 1:
The number 31 fits into 4 0 times, leaving a remainder of 4.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 4 after subtracting 0 from 4.
Append the next digit (0) from the dividend to 4 and continue with: 40 / 31

Going ahead to step 2:
31 goes into 40 1 times with a remainder of 9.
Use 1 as the next digit of our solution. 
Result so far: 1.0
The remainder is 9 after subtracting 31 from 40.
Fetch the next digit (1) from the dividend, attach it to 9 and continue: 91 / 31

Going ahead to step 3:
91 divided by 31 is 2 with a remainder of 29.
The number 2 becomes the next digit in our result. 
Result so far: 12.0
Subtracting 62 from 91 leaves us with 29.
Append the next digit (2) from the dividend to 29 and continue with: 292 / 31

Going ahead to step 4:
292 divided by 31 is 9 with a remainder of 13.
Write down 9 as next digit of the result. 
Result so far: 129.0
If we take 279 away from 292, we end up with 13.
Bring next digit (0) of the dividend behind the 13 and repeat the process: 130 / 31

Advancing to step 5:
The number 31 fits into 130 4 times, leaving a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 1294.0
If we subtract 124 from 130, we get 6.
Bring next digit (9) of the dividend behind the 6 and repeat the process: 69 / 31

Step 6:
69 divided by 31 is 2 with a remainder of 7.
Write down 2 as next digit of the result. 
Result so far: 12942.0
If we take 62 away from 69, we end up 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.

Going ahead to step 7:
If we divide 70 by 31, we get 2 and a remainder of 8.
Record the quotient 2 as the next digit in the result. 
Result so far: 12942.2
If we subtract 62 from 70, we get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Advancing to step 8:
The number 31 fits into 80 2 times, leaving a remainder of 18.
Write down 2 as next digit of the result. 
Result so far: 12942.22
If we take 62 away from 80, we end up with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

The final result is 12942.22 with a remainder of 0.018.