We look at the division of 51840161 by 243 
We're looking to find how many times 243 goes into 51840161.

On to step 1:
When dividing 5 by 243, we get 0 with a remainder of 5.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 5, we end up with 5.
Take the next digit (1) from the dividend and append it to 5, then repeat: 51 / 243

Going ahead to step 2:
When dividing 51 by 243, we get 0 with a remainder of 51.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 51 leaves us with 51.
Append the next digit (8) from the dividend to 51 and continue with: 518 / 243

On to step 3:
518 divided by 243 is 2 with a remainder of 32.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
Subtract 486 from 518 to get 32.
Fetch the next digit (4) from the dividend, attach it to 32 and continue: 324 / 243

Let's proceed to step 4:
The number 243 fits into 324 1 times, leaving a remainder of 81.
Put 1 as the next digit of the answer. 
Result so far: 21.0
If we take 243 away from 324, we end up with 81.
Bring next digit (0) of the dividend behind the 81 and repeat the process: 810 / 243

Step 5:
243 can be fit into 810 3 times, resulting in a remainder of 81.
Use 3 as the next digit of our solution. 
Result so far: 213.0
The remainder is 81 after subtracting 729 from 810.
Fetch the next digit (1) from the dividend, attach it to 81 and continue: 811 / 243

Advancing to step 6:
When dividing 811 by 243, we get 3 with a remainder of 82.
The next digit of our result is 3. 
Result so far: 2133.0
Subtracting 729 from 811 leaves us with 82.
Append the next digit (6) from the dividend to 82 and continue with: 826 / 243

Step 7:
243 goes into 826 3 times with a remainder of 97.
The next digit of our result is 3. 
Result so far: 21333.0
Subtract 729 from 826 to get 97.
Include the next digit (1) from the dividend after 97, then repeat: 971 / 243

Advancing to step 8:
243 can be fit into 971 3 times, resulting in a remainder of 242.
The next digit of our result is 3. 
Result so far: 213333.0
If we subtract 729 from 971, we get 242.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2420, and continue the process.

Moving on to step 9:
243 can be fit into 2420 9 times, resulting in a remainder of 233.
Put 9 as the next digit of the answer. 
Result so far: 213333.9
If we subtract 2187 from 2420, we get 233.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2330, and continue the process.

Let's proceed to step 10:
243 goes into 2330 9 times with a remainder of 143.
Record the quotient 9 as the next digit in the result. 
Result so far: 213333.99
Subtracting 2187 from 2330 leaves us with 143.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1430, and continue the process.

The final outcome is 213333.99, with a leftover of 0.143.