We look at the division of 387091 by 90 
We want to figure out the number of times 387091 can be divided by 90.

On to step 1:
90 can be fit into 3 0 times, resulting in a remainder of 3.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Bring next digit (8) of the dividend behind the 3 and repeat the process: 38 / 90

Step 2:
90 can be fit into 38 0 times, resulting in a remainder of 38.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 38 to get 38.
Take the next digit (7) from the dividend and append it to 38, then repeat: 387 / 90

Step 3:
If we divide 387 by 90, we get 4 and a remainder of 27.
The next digit of our result is 4. 
Result so far: 4.0
Subtracting 360 from 387 leaves us with 27.
Append the next digit (0) from the dividend to 27 and continue with: 270 / 90

Let's proceed to step 4:
The number 90 fits into 270 3 times, leaving a remainder of 0.
The number 3 becomes the next digit in our result. 
Result so far: 43.0
Subtracting 270 from 270 leaves us with 0.
Take the next digit (9) from the dividend and append it to 0, then repeat: 9 / 90

On to step 5:
90 goes into 9 0 times with a remainder of 9.
Record the quotient 0 as the next digit in the result. 
Result so far: 430.0
Deduct 0 from 9 and we're left with 9.
Include the next digit (1) from the dividend after 9, then repeat: 91 / 90

Let's proceed to step 6:
90 can be fit into 91 1 times, resulting in a remainder of 1.
Record the quotient 1 as the next digit in the result. 
Result so far: 4301.0
Subtracting 90 from 91 leaves us with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Moving on to step 7:
The number 90 fits into 10 0 times, leaving a remainder of 10.
Use 0 as the next digit of our solution. 
Result so far: 4301.0
Subtract 0 from 10 to get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Moving on to step 8:
When dividing 100 by 90, we get 1 with a remainder of 10.
Record the quotient 1 as the next digit in the result. 
Result so far: 4301.01
Deduct 90 from 100 and we're left with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Advancing to step 9:
When dividing 100 by 90, we get 1 with a remainder of 10.
Record the quotient 1 as the next digit in the result. 
Result so far: 4301.011
The remainder is 10 after subtracting 90 from 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

The final outcome is 4301.011, with a leftover of 0.001.