Let's divide 436609 by 90
We're looking to find how many times 90 goes into 436609.

On to step 1:
If we divide 4 by 90, we get 0 and a remainder of 4.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 4, we end up with 4.
Take the next digit (3) from the dividend and append it to 4, then repeat: 43 / 90

On to step 2:
90 goes into 43 0 times with a remainder of 43.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 43, we end up with 43.
Bring next digit (6) of the dividend behind the 43 and repeat the process: 436 / 90

Going ahead to step 3:
90 goes into 436 4 times with a remainder of 76.
Use 4 as the next digit of our solution. 
Result so far: 4.0
If we take 360 away from 436, we end up with 76.
Append the next digit (6) from the dividend to 76 and continue with: 766 / 90

Step 4:
The number 90 fits into 766 8 times, leaving a remainder of 46.
The next digit of our result is 8. 
Result so far: 48.0
Subtract 720 from 766 to get 46.
Grab the next digit (0) from the dividend, add it to 46, then carry on: 460 / 90

Moving on to step 5:
90 can be fit into 460 5 times, resulting in a remainder of 10.
Record the quotient 5 as the next digit in the result. 
Result so far: 485.0
The remainder is 10 after subtracting 450 from 460.
Bring next digit (9) of the dividend behind the 10 and repeat the process: 109 / 90

Let's proceed to step 6:
When dividing 109 by 90, we get 1 with a remainder of 19.
The next digit of our result is 1. 
Result so far: 4851.0
If we take 90 away from 109, we end up with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Step 7:
90 goes into 190 2 times with a remainder of 10.
Put 2 as the next digit of the answer. 
Result so far: 4851.2
Deduct 180 from 190 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 8:
If we divide 100 by 90, we get 1 and a remainder of 10.
The number 1 becomes the next digit in our result. 
Result so far: 4851.21
Subtract 90 from 100 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 9:
If we divide 100 by 90, we get 1 and a remainder of 10.
Record the quotient 1 as the next digit in the result. 
Result so far: 4851.211
Subtract 90 from 100 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.

The final outcome is 4851.211, with a leftover of 0.001.