485503 ÷ 21 
We want to figure out the number of times 485503 can be divided by 21.

Let's proceed to step 1:
If we divide 4 by 21, we get 0 and a remainder of 4.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 4, we end up with 4.
Append the next digit (8) from the dividend to 4 and continue with: 48 / 21

On to step 2:
If we divide 48 by 21, we get 2 and a remainder of 6.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
If we take 42 away from 48, we end up with 6.
Grab the next digit (5) from the dividend, add it to 6, then carry on: 65 / 21

Step 3:
21 can be fit into 65 3 times, resulting in a remainder of 2.
The next digit of our result is 3. 
Result so far: 23.0
If we subtract 63 from 65, we get 2.
Fetch the next digit (5) from the dividend, attach it to 2 and continue: 25 / 21

Moving on to step 4:
25 divided by 21 is 1 with a remainder of 4.
Write down 1 as next digit of the result. 
Result so far: 231.0
The remainder is 4 after subtracting 21 from 25.
Grab the next digit (0) from the dividend, add it to 4, then carry on: 40 / 21

Let's proceed to step 5:
21 goes into 40 1 times with a remainder of 19.
Put 1 as the next digit of the answer. 
Result so far: 2311.0
Subtract 21 from 40 to get 19.
Take the next digit (3) from the dividend and append it to 19, then repeat: 193 / 21

Going ahead to step 6:
The number 21 fits into 193 9 times, leaving a remainder of 4.
The number 9 becomes the next digit in our result. 
Result so far: 23119.0
If we subtract 189 from 193, we get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Moving on to step 7:
If we divide 40 by 21, we get 1 and a remainder of 19.
The number 1 becomes the next digit in our result. 
Result so far: 23119.1
The remainder is 19 after subtracting 21 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Advancing to step 8:
When dividing 190 by 21, we get 9 with a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 23119.19
The remainder is 1 after subtracting 189 from 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Step 9:
The number 21 fits into 10 0 times, leaving a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 23119.19
Deduct 0 from 10 and we're left with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Advancing to step 10:
100 divided by 21 is 4 with a remainder of 16.
The number 4 becomes the next digit in our result. 
Result so far: 23119.1904
If we take 84 away from 100, we end up with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Moving on to step 11:
21 goes into 160 7 times with a remainder of 13.
The next digit of our result is 7. 
Result so far: 23119.19047
If we take 147 away from 160, we end up with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

On to step 12:
130 divided by 21 is 6 with a remainder of 4.
Put 6 as the next digit of the answer. 
Result so far: 23119.190476
Subtracting 126 from 130 leaves us with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Going ahead to step 13:
If we divide 40 by 21, we get 1 and a remainder of 19.
The next digit of our result is 1. 
Result so far: 23119.1904761
The remainder is 19 after subtracting 21 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

On to step 14:
When dividing 190 by 21, we get 9 with a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 23119.19047619
Subtract 189 from 190 to get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

The final outcome is 23119.19047619, with a leftover of 1e-09.