We're dividing 549987 by 45 
We want to figure out the number of times 549987 can be divided by 45.

On to step 1:
45 can be fit into 5 0 times, resulting in a remainder of 5.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 5 after subtracting 0 from 5.
Bring next digit (4) of the dividend behind the 5 and repeat the process: 54 / 45

Step 2:
The number 45 fits into 54 1 times, leaving a remainder of 9.
Put 1 as the next digit of the answer. 
Result so far: 1.0
If we subtract 45 from 54, we get 9.
Include the next digit (9) from the dividend after 9, then repeat: 99 / 45

Advancing to step 3:
If we divide 99 by 45, we get 2 and a remainder of 9.
Put 2 as the next digit of the answer. 
Result so far: 12.0
Subtracting 90 from 99 leaves us with 9.
Take the next digit (9) from the dividend and append it to 9, then repeat: 99 / 45

On to step 4:
The number 45 fits into 99 2 times, leaving a remainder of 9.
Write down 2 as next digit of the result. 
Result so far: 122.0
If we subtract 90 from 99, we get 9.
Grab the next digit (8) from the dividend, add it to 9, then carry on: 98 / 45

Going ahead to step 5:
The number 45 fits into 98 2 times, leaving a remainder of 8.
Put 2 as the next digit of the answer. 
Result so far: 1222.0
If we take 90 away from 98, we end up with 8.
Include the next digit (7) from the dividend after 8, then repeat: 87 / 45

Advancing to step 6:
45 can be fit into 87 1 times, resulting in a remainder of 42.
The number 1 becomes the next digit in our result. 
Result so far: 12221.0
The remainder is 42 after subtracting 45 from 87.
Since there are no more digits in the dividend, we add a zero to the remainder making it 420, and continue the process.

Moving on to step 7:
45 goes into 420 9 times with a remainder of 15.
The number 9 becomes the next digit in our result. 
Result so far: 12221.9
Deduct 405 from 420 and we're left with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Going ahead to step 8:
45 can be fit into 150 3 times, resulting in a remainder of 15.
Put 3 as the next digit of the answer. 
Result so far: 12221.93
Deduct 135 from 150 and we're left with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Going ahead to step 9:
150 divided by 45 is 3 with a remainder of 15.
Use 3 as the next digit of our solution. 
Result so far: 12221.933
Subtract 135 from 150 to get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Our division results in 12221.933 with a remaining 0.0015.