358470 ÷ 21 
Let's see how many times 21 fits into 358470.

On to step 1:
3 divided by 21 is 0 with a remainder of 3.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Take the next digit (5) from the dividend and append it to 3, then repeat: 35 / 21

On to step 2:
The number 21 fits into 35 1 times, leaving a remainder of 14.
Use 1 as the next digit of our solution. 
Result so far: 1.0
If we take 21 away from 35, we end up with 14.
Append the next digit (8) from the dividend to 14 and continue with: 148 / 21

On to step 3:
21 goes into 148 7 times with a remainder of 1.
Write down 7 as next digit of the result. 
Result so far: 17.0
If we take 147 away from 148, we end up with 1.
Grab the next digit (4) from the dividend, add it to 1, then carry on: 14 / 21

Step 4:
The number 21 fits into 14 0 times, leaving a remainder of 14.
The number 0 becomes the next digit in our result. 
Result so far: 170.0
Subtract 0 from 14 to get 14.
Take the next digit (7) from the dividend and append it to 14, then repeat: 147 / 21

Going ahead to step 5:
21 can be fit into 147 7 times, resulting in a remainder of 0.
The number 7 becomes the next digit in our result. 
Result so far: 1707.0
If we subtract 147 from 147, we get 0.
Bring next digit (0) of the dividend behind the 0 and repeat the process: 0 / 21

Advancing to step 6:
When dividing 0 by 21, we get 0 with a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 17070.0
The remainder is 0 after subtracting 0 from 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Advancing to step 7:
The number 21 fits into 0 0 times, leaving a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 17070.0
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Going ahead to step 8:
If we divide 0 by 21, we get 0 and a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 17070.0
Subtract 0 from 0 to get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

In conclusion, the division gives 17070.0 with a balance of 0.0.