87138221 ÷ 511 
We want to figure out the number of times 87138221 can be divided by 511.

Step 1:
If we divide 8 by 511, we get 0 and a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 8 and we're left with 8.
Fetch the next digit (7) from the dividend, attach it to 8 and continue: 87 / 511

Let's proceed to step 2:
511 goes into 87 0 times with a remainder of 87.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 87 and we're left with 87.
Append the next digit (1) from the dividend to 87 and continue with: 871 / 511

Moving on to step 3:
511 goes into 871 1 times with a remainder of 360.
The next digit of our result is 1. 
Result so far: 1.0
If we take 511 away from 871, we end up with 360.
Append the next digit (3) from the dividend to 360 and continue with: 3603 / 511

Going ahead to step 4:
511 can be fit into 3603 7 times, resulting in a remainder of 26.
Use 7 as the next digit of our solution. 
Result so far: 17.0
The remainder is 26 after subtracting 3577 from 3603.
Take the next digit (8) from the dividend and append it to 26, then repeat: 268 / 511

Going ahead to step 5:
511 goes into 268 0 times with a remainder of 268.
Write down 0 as next digit of the result. 
Result so far: 170.0
The remainder is 268 after subtracting 0 from 268.
Fetch the next digit (2) from the dividend, attach it to 268 and continue: 2682 / 511

Advancing to step 6:
When dividing 2682 by 511, we get 5 with a remainder of 127.
Record the quotient 5 as the next digit in the result. 
Result so far: 1705.0
Deduct 2555 from 2682 and we're left with 127.
Grab the next digit (2) from the dividend, add it to 127, then carry on: 1272 / 511

Let's proceed to step 7:
The number 511 fits into 1272 2 times, leaving a remainder of 250.
The number 2 becomes the next digit in our result. 
Result so far: 17052.0
Subtracting 1022 from 1272 leaves us with 250.
Take the next digit (1) from the dividend and append it to 250, then repeat: 2501 / 511

Moving on to step 8:
2501 divided by 511 is 4 with a remainder of 457.
The next digit of our result is 4. 
Result so far: 170524.0
If we subtract 2044 from 2501, we get 457.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4570, and continue the process.

Advancing to step 9:
When dividing 4570 by 511, we get 8 with a remainder of 482.
The next digit of our result is 8. 
Result so far: 170524.8
If we subtract 4088 from 4570, we get 482.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4820, and continue the process.

Step 10:
The number 511 fits into 4820 9 times, leaving a remainder of 221.
Record the quotient 9 as the next digit in the result. 
Result so far: 170524.89
If we take 4599 away from 4820, we end up with 221.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2210, and continue the process.

On to step 11:
511 can be fit into 2210 4 times, resulting in a remainder of 166.
Record the quotient 4 as the next digit in the result. 
Result so far: 170524.894
If we take 2044 away from 2210, we end up with 166.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1660, and continue the process.

Step 12:
511 goes into 1660 3 times with a remainder of 127.
Put 3 as the next digit of the answer. 
Result so far: 170524.8943
If we subtract 1533 from 1660, we get 127.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1270, and continue the process.

Step 13:
1270 divided by 511 is 2 with a remainder of 248.
Write down 2 as next digit of the result. 
Result so far: 170524.89432
If we subtract 1022 from 1270, we get 248.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2480, and continue the process.

Moving on to step 14:
2480 divided by 511 is 4 with a remainder of 436.
The next digit of our result is 4. 
Result so far: 170524.894324
If we take 2044 away from 2480, we end up with 436.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4360, and continue the process.

Going ahead to step 15:
511 can be fit into 4360 8 times, resulting in a remainder of 272.
Record the quotient 8 as the next digit in the result. 
Result so far: 170524.8943248
Deduct 4088 from 4360 and we're left with 272.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2720, and continue the process.

Going ahead to step 16:
When dividing 2720 by 511, we get 5 with a remainder of 165.
Record the quotient 5 as the next digit in the result. 
Result so far: 170524.89432485
If we subtract 2555 from 2720, we get 165.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1650, and continue the process.

Our division results in 170524.89432485 with a remaining 1.65e-07.