We divide 391921 by 90
Let's see how many times 90 fits into 391921.

Step 1:
90 goes into 3 0 times with a remainder of 3.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Grab the next digit (9) from the dividend, add it to 3, then carry on: 39 / 90

Moving on to step 2:
90 can be fit into 39 0 times, resulting in a remainder of 39.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 39 leaves us with 39.
Append the next digit (1) from the dividend to 39 and continue with: 391 / 90

Moving on to step 3:
When dividing 391 by 90, we get 4 with a remainder of 31.
Write down 4 as next digit of the result. 
Result so far: 4.0
The remainder is 31 after subtracting 360 from 391.
Bring next digit (9) of the dividend behind the 31 and repeat the process: 319 / 90

Advancing to step 4:
90 goes into 319 3 times with a remainder of 49.
Write down 3 as next digit of the result. 
Result so far: 43.0
Subtract 270 from 319 to get 49.
Fetch the next digit (2) from the dividend, attach it to 49 and continue: 492 / 90

Let's proceed to step 5:
90 goes into 492 5 times with a remainder of 42.
Put 5 as the next digit of the answer. 
Result so far: 435.0
Subtract 450 from 492 to get 42.
Bring next digit (1) of the dividend behind the 42 and repeat the process: 421 / 90

Let's proceed to step 6:
90 goes into 421 4 times with a remainder of 61.
Write down 4 as next digit of the result. 
Result so far: 4354.0
If we subtract 360 from 421, we get 61.
Since there are no more digits in the dividend, we add a zero to the remainder making it 610, and continue the process.

On to step 7:
90 goes into 610 6 times with a remainder of 70.
The number 6 becomes the next digit in our result. 
Result so far: 4354.6
Subtract 540 from 610 to get 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

Moving on to step 8:
When dividing 700 by 90, we get 7 with a remainder of 70.
Put 7 as the next digit of the answer. 
Result so far: 4354.67
Subtracting 630 from 700 leaves us with 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

Moving on to step 9:
90 goes into 700 7 times with a remainder of 70.
Use 7 as the next digit of our solution. 
Result so far: 4354.677
Subtract 630 from 700 to get 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

The quotient of the division is 4354.677, and the remainder is 0.007.