We divide 51309091 by 800
We're looking to find how many times 800 goes into 51309091.

On to step 1:
800 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.
Append the next digit (1) from the dividend to 5 and continue with: 51 / 800

Advancing to step 2:
If we divide 51 by 800, we get 0 and a remainder of 51.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 51 after subtracting 0 from 51.
Bring next digit (3) of the dividend behind the 51 and repeat the process: 513 / 800

On to step 3:
When dividing 513 by 800, we get 0 with a remainder of 513.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 513 to get 513.
Append the next digit (0) from the dividend to 513 and continue with: 5130 / 800

Moving on to step 4:
800 can be fit into 5130 6 times, resulting in a remainder of 330.
The next digit of our result is 6. 
Result so far: 6.0
If we subtract 4800 from 5130, we get 330.
Append the next digit (9) from the dividend to 330 and continue with: 3309 / 800

Step 5:
800 goes into 3309 4 times with a remainder of 109.
Record the quotient 4 as the next digit in the result. 
Result so far: 64.0
The remainder is 109 after subtracting 3200 from 3309.
Fetch the next digit (0) from the dividend, attach it to 109 and continue: 1090 / 800

Let's proceed to step 6:
800 can be fit into 1090 1 times, resulting in a remainder of 290.
Put 1 as the next digit of the answer. 
Result so far: 641.0
Subtract 800 from 1090 to get 290.
Bring next digit (9) of the dividend behind the 290 and repeat the process: 2909 / 800

Going ahead to step 7:
800 goes into 2909 3 times with a remainder of 509.
Use 3 as the next digit of our solution. 
Result so far: 6413.0
If we take 2400 away from 2909, we end up with 509.
Grab the next digit (1) from the dividend, add it to 509, then carry on: 5091 / 800

Step 8:
800 can be fit into 5091 6 times, resulting in a remainder of 291.
Put 6 as the next digit of the answer. 
Result so far: 64136.0
Subtract 4800 from 5091 to get 291.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2910, and continue the process.

On to step 9:
2910 divided by 800 is 3 with a remainder of 510.
Record the quotient 3 as the next digit in the result. 
Result so far: 64136.3
If we subtract 2400 from 2910, we get 510.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5100, and continue the process.

Advancing to step 10:
800 goes into 5100 6 times with a remainder of 300.
The next digit of our result is 6. 
Result so far: 64136.36
If we subtract 4800 from 5100, we get 300.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3000, and continue the process.

Step 11:
The number 800 fits into 3000 3 times, leaving a remainder of 600.
The number 3 becomes the next digit in our result. 
Result so far: 64136.363
Deduct 2400 from 3000 and we're left with 600.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6000, and continue the process.

Step 12:
800 can be fit into 6000 7 times, resulting in a remainder of 400.
Record the quotient 7 as the next digit in the result. 
Result so far: 64136.3637
Deduct 5600 from 6000 and we're left with 400.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4000, and continue the process.

Moving on to step 13:
When dividing 4000 by 800, we get 5 with a remainder of 0.
Use 5 as the next digit of our solution. 
Result so far: 64136.36375
The remainder is 0 after subtracting 4000 from 4000.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Going ahead to step 14:
800 goes into 0 0 times with a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 64136.36375
If we take 0 away from 0, we end up with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

On to step 15:
If we divide 0 by 800, we get 0 and a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 64136.36375
Subtract 0 from 0 to get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

After the division, we end up with 64136.36375 and a remainder of 0.0.