870047 ÷ 21 
Let's see how many times 21 fits into 870047.

Step 1:
The number 21 fits into 8 0 times, leaving a remainder of 8.
Use 0 as the next digit of our solution. 
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.
Put 4 as the next digit of the answer. 
Result so far: 4.0
Subtracting 84 from 87 leaves us with 3.
Grab the next digit (0) from the dividend, add it to 3, then carry on: 30 / 21

On to step 3:
21 can be fit into 30 1 times, resulting in a remainder of 9.
The number 1 becomes the next digit in our result. 
Result so far: 41.0
Deduct 21 from 30 and we're left with 9.
Fetch the next digit (0) from the dividend, attach it to 9 and continue: 90 / 21

Advancing to step 4:
The number 21 fits into 90 4 times, leaving a remainder of 6.
The next digit of our result is 4. 
Result so far: 414.0
If we take 84 away from 90, we end up with 6.
Grab the next digit (4) from the dividend, add it to 6, then carry on: 64 / 21

Moving on to step 5:
The number 21 fits into 64 3 times, leaving a remainder of 1.
The next digit of our result is 3. 
Result so far: 4143.0
Deduct 63 from 64 and we're left with 1.
Take the next digit (7) from the dividend and append it to 1, then repeat: 17 / 21

Moving on to step 6:
21 can be fit into 17 0 times, resulting in a remainder of 17.
Write down 0 as next digit of the result. 
Result so far: 41430.0
If we take 0 away from 17, we end up with 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 7:
If we divide 170 by 21, we get 8 and a remainder of 2.
Record the quotient 8 as the next digit in the result. 
Result so far: 41430.8
Deduct 168 from 170 and we're left 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.

Let's proceed to step 8:
21 can be fit into 20 0 times, resulting in a remainder of 20.
Record the quotient 0 as the next digit in the result. 
Result so far: 41430.8
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.

Moving on to step 9:
When dividing 200 by 21, we get 9 with a remainder of 11.
Record the quotient 9 as the next digit in the result. 
Result so far: 41430.809
If we take 189 away from 200, we end up 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.

Moving on to step 10:
21 can be fit into 110 5 times, resulting in a remainder of 5.
Put 5 as the next digit of the answer. 
Result so far: 41430.8095
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.

Let's proceed to step 11:
21 goes into 50 2 times with a remainder of 8.
The number 2 becomes the next digit in our result. 
Result so far: 41430.80952
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 12:
If we divide 80 by 21, we get 3 and a remainder of 17.
The next digit of our result is 3. 
Result so far: 41430.809523
Subtracting 63 from 80 leaves us with 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Going ahead to step 13:
If we divide 170 by 21, we get 8 and a remainder of 2.
Write down 8 as next digit of the result. 
Result so far: 41430.8095238
Subtracting 168 from 170 leaves us 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.

Let's proceed to step 14:
When dividing 20 by 21, we get 0 with a remainder of 20.
Use 0 as the next digit of our solution. 
Result so far: 41430.8095238
Subtract 0 from 20 to get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

The final result is 41430.8095238 with a remainder of 2e-08.