187409 ÷ 21 
Let's see how many times 21 fits into 187409.

Let's proceed to step 1:
When dividing 1 by 21, we get 0 with a remainder of 1.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 1 after subtracting 0 from 1.
Take the next digit (8) from the dividend and append it to 1, then repeat: 18 / 21

On to step 2:
21 goes into 18 0 times with a remainder of 18.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 18 to get 18.
Grab the next digit (7) from the dividend, add it to 18, then carry on: 187 / 21

Let's proceed to step 3:
21 can be fit into 187 8 times, resulting in a remainder of 19.
Use 8 as the next digit of our solution. 
Result so far: 8.0
If we take 168 away from 187, we end up with 19.
Append the next digit (4) from the dividend to 19 and continue with: 194 / 21

Let's proceed to step 4:
21 can be fit into 194 9 times, resulting in a remainder of 5.
Use 9 as the next digit of our solution. 
Result so far: 89.0
The remainder is 5 after subtracting 189 from 194.
Grab the next digit (0) from the dividend, add it to 5, then carry on: 50 / 21

Step 5:
The number 21 fits into 50 2 times, leaving a remainder of 8.
Record the quotient 2 as the next digit in the result. 
Result so far: 892.0
If we subtract 42 from 50, we get 8.
Include the next digit (9) from the dividend after 8, then repeat: 89 / 21

Going ahead to step 6:
89 divided by 21 is 4 with a remainder of 5.
The number 4 becomes the next digit in our result. 
Result so far: 8924.0
If we take 84 away from 89, we end up with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Going ahead to step 7:
21 can be fit into 50 2 times, resulting in a remainder of 8.
Put 2 as the next digit of the answer. 
Result so far: 8924.2
Deduct 42 from 50 and we're left 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.

Going ahead to step 8:
21 can be fit into 80 3 times, resulting in a remainder of 17.
The next digit of our result is 3. 
Result so far: 8924.23
The remainder is 17 after subtracting 63 from 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Step 9:
The number 21 fits into 170 8 times, leaving a remainder of 2.
Use 8 as the next digit of our solution. 
Result so far: 8924.238
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.

Advancing to step 10:
20 divided by 21 is 0 with a remainder of 20.
The number 0 becomes the next digit in our result. 
Result so far: 8924.238
Subtracting 0 from 20 leaves us 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.

Let's proceed to step 11:
The number 21 fits into 200 9 times, leaving a remainder of 11.
The next digit of our result is 9. 
Result so far: 8924.23809
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 12:
21 goes into 110 5 times with a remainder of 5.
The number 5 becomes the next digit in our result. 
Result so far: 8924.238095
Subtracting 105 from 110 leaves us with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

On to step 13:
If we divide 50 by 21, we get 2 and a remainder of 8.
The next digit of our result is 2. 
Result so far: 8924.2380952
The remainder is 8 after subtracting 42 from 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Advancing to step 14:
21 can be fit into 80 3 times, resulting in a remainder of 17.
Put 3 as the next digit of the answer. 
Result so far: 8924.23809523
Deduct 63 from 80 and we're left 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.

In conclusion, the division gives 8924.23809523 with a balance of 1.7e-08.