612521 ÷ 21 
We're looking to find how many times 21 goes into 612521.

Step 1:
21 goes into 6 0 times with a remainder of 6.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 6 to get 6.
Grab the next digit (1) from the dividend, add it to 6, then carry on: 61 / 21

Step 2:
When dividing 61 by 21, we get 2 with a remainder of 19.
The next digit of our result is 2. 
Result so far: 2.0
Deduct 42 from 61 and we're left with 19.
Append the next digit (2) from the dividend to 19 and continue with: 192 / 21

Let's proceed to step 3:
When dividing 192 by 21, we get 9 with a remainder of 3.
Use 9 as the next digit of our solution. 
Result so far: 29.0
If we take 189 away from 192, we end up with 3.
Fetch the next digit (5) from the dividend, attach it to 3 and continue: 35 / 21

Advancing to step 4:
When dividing 35 by 21, we get 1 with a remainder of 14.
Put 1 as the next digit of the answer. 
Result so far: 291.0
Subtracting 21 from 35 leaves us with 14.
Fetch the next digit (2) from the dividend, attach it to 14 and continue: 142 / 21

On to step 5:
142 divided by 21 is 6 with a remainder of 16.
Record the quotient 6 as the next digit in the result. 
Result so far: 2916.0
Subtract 126 from 142 to get 16.
Fetch the next digit (1) from the dividend, attach it to 16 and continue: 161 / 21

On to step 6:
21 can be fit into 161 7 times, resulting in a remainder of 14.
Write down 7 as next digit of the result. 
Result so far: 29167.0
If we subtract 147 from 161, we get 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Let's proceed to step 7:
140 divided by 21 is 6 with a remainder of 14.
Write down 6 as next digit of the result. 
Result so far: 29167.6
Subtracting 126 from 140 leaves us with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Let's proceed to step 8:
140 divided by 21 is 6 with a remainder of 14.
Put 6 as the next digit of the answer. 
Result so far: 29167.66
Deduct 126 from 140 and we're left with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

The final result is 29167.66 with a remainder of 0.014.