84210423 ÷ 843 
Let's see how many times 843 fits into 84210423.

Step 1:
843 goes into 8 0 times with a remainder of 8.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 8 leaves us with 8.
Append the next digit (4) from the dividend to 8 and continue with: 84 / 843

Let's proceed to step 2:
The number 843 fits into 84 0 times, leaving a remainder of 84.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 84 to get 84.
Grab the next digit (2) from the dividend, add it to 84, then carry on: 842 / 843

Advancing to step 3:
843 goes into 842 0 times with a remainder of 842.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 842, we get 842.
Include the next digit (1) from the dividend after 842, then repeat: 8421 / 843

Going ahead to step 4:
When dividing 8421 by 843, we get 9 with a remainder of 834.
Record the quotient 9 as the next digit in the result. 
Result so far: 9.0
Deduct 7587 from 8421 and we're left with 834.
Bring next digit (0) of the dividend behind the 834 and repeat the process: 8340 / 843

Advancing to step 5:
When dividing 8340 by 843, we get 9 with a remainder of 753.
The next digit of our result is 9. 
Result so far: 99.0
If we subtract 7587 from 8340, we get 753.
Grab the next digit (4) from the dividend, add it to 753, then carry on: 7534 / 843

Step 6:
When dividing 7534 by 843, we get 8 with a remainder of 790.
Write down 8 as next digit of the result. 
Result so far: 998.0
If we subtract 6744 from 7534, we get 790.
Fetch the next digit (2) from the dividend, attach it to 790 and continue: 7902 / 843

Moving on to step 7:
The number 843 fits into 7902 9 times, leaving a remainder of 315.
The next digit of our result is 9. 
Result so far: 9989.0
Subtract 7587 from 7902 to get 315.
Fetch the next digit (3) from the dividend, attach it to 315 and continue: 3153 / 843

Step 8:
843 goes into 3153 3 times with a remainder of 624.
Write down 3 as next digit of the result. 
Result so far: 99893.0
If we subtract 2529 from 3153, we get 624.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6240, and continue the process.

Going ahead to step 9:
843 can be fit into 6240 7 times, resulting in a remainder of 339.
Put 7 as the next digit of the answer. 
Result so far: 99893.7
Subtracting 5901 from 6240 leaves us with 339.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3390, and continue the process.

Advancing to step 10:
The number 843 fits into 3390 4 times, leaving a remainder of 18.
The next digit of our result is 4. 
Result so far: 99893.74
If we take 3372 away from 3390, we end up with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Going ahead to step 11:
When dividing 180 by 843, we get 0 with a remainder of 180.
Use 0 as the next digit of our solution. 
Result so far: 99893.74
If we subtract 0 from 180, we get 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1800, and continue the process.

Moving on to step 12:
If we divide 1800 by 843, we get 2 and a remainder of 114.
Put 2 as the next digit of the answer. 
Result so far: 99893.7402
Subtracting 1686 from 1800 leaves us with 114.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1140, and continue the process.

Moving on to step 13:
843 goes into 1140 1 times with a remainder of 297.
The number 1 becomes the next digit in our result. 
Result so far: 99893.74021
If we subtract 843 from 1140, we get 297.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2970, and continue the process.

Step 14:
If we divide 2970 by 843, we get 3 and a remainder of 441.
Write down 3 as next digit of the result. 
Result so far: 99893.740213
If we subtract 2529 from 2970, we get 441.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4410, and continue the process.

Step 15:
When dividing 4410 by 843, we get 5 with a remainder of 195.
Use 5 as the next digit of our solution. 
Result so far: 99893.7402135
If we subtract 4215 from 4410, we get 195.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1950, and continue the process.

Going ahead to step 16:
If we divide 1950 by 843, we get 2 and a remainder of 264.
The next digit of our result is 2. 
Result so far: 99893.74021352
If we subtract 1686 from 1950, we get 264.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2640, and continue the process.

After the division, we end up with 99893.74021352 and a remainder of 2.64e-07.