399164 ÷ 51 
We're looking to find how many times 51 goes into 399164.

Step 1:
51 can be fit into 3 0 times, resulting in a remainder of 3.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 3 and we're left with 3.
Include the next digit (9) from the dividend after 3, then repeat: 39 / 51

Step 2:
When dividing 39 by 51, we get 0 with a remainder of 39.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 39, we get 39.
Grab the next digit (9) from the dividend, add it to 39, then carry on: 399 / 51

On to step 3:
51 goes into 399 7 times with a remainder of 42.
Write down 7 as next digit of the result. 
Result so far: 7.0
Deduct 357 from 399 and we're left with 42.
Take the next digit (1) from the dividend and append it to 42, then repeat: 421 / 51

Moving on to step 4:
The number 51 fits into 421 8 times, leaving a remainder of 13.
Record the quotient 8 as the next digit in the result. 
Result so far: 78.0
Subtract 408 from 421 to get 13.
Fetch the next digit (6) from the dividend, attach it to 13 and continue: 136 / 51

Step 5:
If we divide 136 by 51, we get 2 and a remainder of 34.
Put 2 as the next digit of the answer. 
Result so far: 782.0
If we subtract 102 from 136, we get 34.
Append the next digit (4) from the dividend to 34 and continue with: 344 / 51

On to step 6:
51 can be fit into 344 6 times, resulting in a remainder of 38.
The next digit of our result is 6. 
Result so far: 7826.0
Subtract 306 from 344 to get 38.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

Let's proceed to step 7:
When dividing 380 by 51, we get 7 with a remainder of 23.
Write down 7 as next digit of the result. 
Result so far: 7826.7
If we subtract 357 from 380, we get 23.
Since there are no more digits in the dividend, we add a zero to the remainder making it 230, and continue the process.

Moving on to step 8:
51 can be fit into 230 4 times, resulting in a remainder of 26.
Write down 4 as next digit of the result. 
Result so far: 7826.74
If we take 204 away from 230, we end up with 26.
Since there are no more digits in the dividend, we add a zero to the remainder making it 260, and continue the process.

Let's proceed to step 9:
260 divided by 51 is 5 with a remainder of 5.
Write down 5 as next digit of the result. 
Result so far: 7826.745
Subtract 255 from 260 to get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Advancing to step 10:
The number 51 fits into 50 0 times, leaving a remainder of 50.
Record the quotient 0 as the next digit in the result. 
Result so far: 7826.745
If we take 0 away from 50, we end up with 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Advancing to step 11:
51 can be fit into 500 9 times, resulting in a remainder of 41.
Put 9 as the next digit of the answer. 
Result so far: 7826.74509
Subtract 459 from 500 to get 41.
Since there are no more digits in the dividend, we add a zero to the remainder making it 410, and continue the process.

Moving on to step 12:
When dividing 410 by 51, we get 8 with a remainder of 2.
The number 8 becomes the next digit in our result. 
Result so far: 7826.745098
If we subtract 408 from 410, we get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Advancing to step 13:
The number 51 fits into 20 0 times, leaving a remainder of 20.
The next digit of our result is 0. 
Result so far: 7826.745098
The remainder is 20 after subtracting 0 from 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Advancing to step 14:
51 can be fit into 200 3 times, resulting in a remainder of 47.
Put 3 as the next digit of the answer. 
Result so far: 7826.74509803
Subtracting 153 from 200 leaves us with 47.
Since there are no more digits in the dividend, we add a zero to the remainder making it 470, and continue the process.

The quotient of the division is 7826.74509803, and the remainder is 4.7e-08.