358680 ÷ 21 
Our goal is to divide 358680 by 21.

Step 1:
21 can be fit into 3 0 times, resulting in a remainder of 3.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Include the next digit (5) from the dividend after 3, then repeat: 35 / 21

Advancing to step 2:
35 divided by 21 is 1 with a remainder of 14.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Subtracting 21 from 35 leaves us with 14.
Take the next digit (8) from the dividend and append it to 14, then repeat: 148 / 21

Moving on to step 3:
The number 21 fits into 148 7 times, leaving a remainder of 1.
The next digit of our result is 7. 
Result so far: 17.0
If we take 147 away from 148, we end up with 1.
Append the next digit (6) from the dividend to 1 and continue with: 16 / 21

Let's proceed to step 4:
If we divide 16 by 21, we get 0 and a remainder of 16.
Write down 0 as next digit of the result. 
Result so far: 170.0
If we subtract 0 from 16, we get 16.
Take the next digit (8) from the dividend and append it to 16, then repeat: 168 / 21

Going ahead to step 5:
168 divided by 21 is 8 with a remainder of 0.
Use 8 as the next digit of our solution. 
Result so far: 1708.0
Subtracting 168 from 168 leaves us with 0.
Append the next digit (0) from the dividend to 0 and continue with: 0 / 21

Moving on to step 6:
0 divided by 21 is 0 with a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 17080.0
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.

Moving on 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: 17080.0
If we take 0 away from 0, we end up 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.

On to step 8:
When dividing 0 by 21, we get 0 with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 17080.0
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.

The final outcome is 17080.0, with a leftover of 0.0.