We're dividing 45191 by 90 
We want to divide 45191 by 90.

Step 1:
When dividing 4 by 90, we get 0 with a remainder of 4.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 4 and we're left with 4.
Take the next digit (5) from the dividend and append it to 4, then repeat: 45 / 90

Step 2:
90 goes into 45 0 times with a remainder of 45.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 45 and we're left with 45.
Append the next digit (1) from the dividend to 45 and continue with: 451 / 90

Going ahead to step 3:
90 goes into 451 5 times with a remainder of 1.
Put 5 as the next digit of the answer. 
Result so far: 5.0
Subtract 450 from 451 to get 1.
Append the next digit (9) from the dividend to 1 and continue with: 19 / 90

Going ahead to step 4:
19 divided by 90 is 0 with a remainder of 19.
Record the quotient 0 as the next digit in the result. 
Result so far: 50.0
The remainder is 19 after subtracting 0 from 19.
Fetch the next digit (1) from the dividend, attach it to 19 and continue: 191 / 90

Let's proceed to step 5:
When dividing 191 by 90, we get 2 with a remainder of 11.
The next digit of our result is 2. 
Result so far: 502.0
The remainder is 11 after subtracting 180 from 191.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Going ahead to step 6:
90 can be fit into 110 1 times, resulting in a remainder of 20.
Put 1 as the next digit of the answer. 
Result so far: 502.1
If we subtract 90 from 110, we get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Moving on to step 7:
90 can be fit into 200 2 times, resulting in a remainder of 20.
Record the quotient 2 as the next digit in the result. 
Result so far: 502.12
Subtract 180 from 200 to get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Moving on to step 8:
90 can be fit into 200 2 times, resulting in a remainder of 20.
Write down 2 as next digit of the result. 
Result so far: 502.122
Subtracting 180 from 200 leaves us with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

After the division, we end up with 502.122 and a remainder of 0.002.