We look at the division of 876959 by 21 
We want to figure out the number of times 876959 can be divided by 21.

Going ahead to step 1:
The number 21 fits into 8 0 times, leaving a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 8 to get 8.
Fetch the next digit (7) from the dividend, attach it to 8 and continue: 87 / 21

Step 2:
When dividing 87 by 21, we get 4 with a remainder of 3.
Use 4 as the next digit of our solution. 
Result so far: 4.0
Subtract 84 from 87 to get 3.
Bring next digit (6) of the dividend behind the 3 and repeat the process: 36 / 21

Going ahead to step 3:
If we divide 36 by 21, we get 1 and a remainder of 15.
The next digit of our result is 1. 
Result so far: 41.0
Deduct 21 from 36 and we're left with 15.
Bring next digit (9) of the dividend behind the 15 and repeat the process: 159 / 21

On to step 4:
If we divide 159 by 21, we get 7 and a remainder of 12.
Write down 7 as next digit of the result. 
Result so far: 417.0
The remainder is 12 after subtracting 147 from 159.
Bring next digit (5) of the dividend behind the 12 and repeat the process: 125 / 21

Advancing to step 5:
21 can be fit into 125 5 times, resulting in a remainder of 20.
Put 5 as the next digit of the answer. 
Result so far: 4175.0
Deduct 105 from 125 and we're left with 20.
Take the next digit (9) from the dividend and append it to 20, then repeat: 209 / 21

Step 6:
209 divided by 21 is 9 with a remainder of 20.
The next digit of our result is 9. 
Result so far: 41759.0
Deduct 189 from 209 and we're left with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Going ahead to step 7:
When dividing 200 by 21, we get 9 with a remainder of 11.
The next digit of our result is 9. 
Result so far: 41759.9
Deduct 189 from 200 and we're left with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Let's proceed to step 8:
21 can be fit into 110 5 times, resulting in a remainder of 5.
The number 5 becomes the next digit in our result. 
Result so far: 41759.95
Subtract 105 from 110 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.

Step 9:
50 divided by 21 is 2 with a remainder of 8.
Write down 2 as next digit of the result. 
Result so far: 41759.952
Subtracting 42 from 50 leaves us with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Step 10:
21 can be fit into 80 3 times, resulting in a remainder of 17.
The number 3 becomes the next digit in our result. 
Result so far: 41759.9523
Subtract 63 from 80 to get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Moving on to step 11:
When dividing 170 by 21, we get 8 with a remainder of 2.
The next digit of our result is 8. 
Result so far: 41759.95238
If we take 168 away from 170, we end up with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

On to step 12:
21 can be fit into 20 0 times, resulting in a remainder of 20.
Put 0 as the next digit of the answer. 
Result so far: 41759.95238
If we take 0 away from 20, we end up with 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 13:
When dividing 200 by 21, we get 9 with a remainder of 11.
Put 9 as the next digit of the answer. 
Result so far: 41759.9523809
Deduct 189 from 200 and we're left with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Step 14:
When dividing 110 by 21, we get 5 with a remainder of 5.
Use 5 as the next digit of our solution. 
Result so far: 41759.95238095
If we subtract 105 from 110, we 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.

In conclusion, the division gives 41759.95238095 with a balance of 5e-09.