Let's divide 387721 by 90
We're looking to find how many times 90 goes into 387721.

Moving on to step 1:
3 divided by 90 is 0 with a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 3 and we're left with 3.
Include the next digit (8) from the dividend after 3, then repeat: 38 / 90

On to step 2:
The number 90 fits into 38 0 times, leaving a remainder of 38.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 38 to get 38.
Bring next digit (7) of the dividend behind the 38 and repeat the process: 387 / 90

On to step 3:
The number 90 fits into 387 4 times, leaving a remainder of 27.
Put 4 as the next digit of the answer. 
Result so far: 4.0
Deduct 360 from 387 and we're left with 27.
Fetch the next digit (7) from the dividend, attach it to 27 and continue: 277 / 90

Step 4:
When dividing 277 by 90, we get 3 with a remainder of 7.
The number 3 becomes the next digit in our result. 
Result so far: 43.0
Deduct 270 from 277 and we're left with 7.
Append the next digit (2) from the dividend to 7 and continue with: 72 / 90

Let's proceed to step 5:
72 divided by 90 is 0 with a remainder of 72.
Record the quotient 0 as the next digit in the result. 
Result so far: 430.0
If we subtract 0 from 72, we get 72.
Bring next digit (1) of the dividend behind the 72 and repeat the process: 721 / 90

On to step 6:
90 can be fit into 721 8 times, resulting in a remainder of 1.
Record the quotient 8 as the next digit in the result. 
Result so far: 4308.0
Deduct 720 from 721 and we're left 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:
90 goes into 10 0 times with a remainder of 10.
Use 0 as the next digit of our solution. 
Result so far: 4308.0
Deduct 0 from 10 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.

Step 8:
90 goes into 100 1 times with a remainder of 10.
Use 1 as the next digit of our solution. 
Result so far: 4308.01
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.

On to step 9:
The number 90 fits into 100 1 times, leaving a remainder of 10.
The next digit of our result is 1. 
Result so far: 4308.011
If we subtract 90 from 100, we 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.

Our division results in 4308.011 with a remaining 0.001.