We're dividing 21231686 by 603 
We want to divide 21231686 by 603.

Step 1:
The number 603 fits into 2 0 times, leaving a remainder of 2.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 2 after subtracting 0 from 2.
Append the next digit (1) from the dividend to 2 and continue with: 21 / 603

Let's proceed to step 2:
When dividing 21 by 603, we get 0 with a remainder of 21.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 21 and we're left with 21.
Bring next digit (2) of the dividend behind the 21 and repeat the process: 212 / 603

On to step 3:
The number 603 fits into 212 0 times, leaving a remainder of 212.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 212 after subtracting 0 from 212.
Take the next digit (3) from the dividend and append it to 212, then repeat: 2123 / 603

Going ahead to step 4:
If we divide 2123 by 603, we get 3 and a remainder of 314.
Write down 3 as next digit of the result. 
Result so far: 3.0
If we take 1809 away from 2123, we end up with 314.
Grab the next digit (1) from the dividend, add it to 314, then carry on: 3141 / 603

Advancing to step 5:
If we divide 3141 by 603, we get 5 and a remainder of 126.
The next digit of our result is 5. 
Result so far: 35.0
If we subtract 3015 from 3141, we get 126.
Bring next digit (6) of the dividend behind the 126 and repeat the process: 1266 / 603

Going ahead to step 6:
When dividing 1266 by 603, we get 2 with a remainder of 60.
Put 2 as the next digit of the answer. 
Result so far: 352.0
Subtracting 1206 from 1266 leaves us with 60.
Bring next digit (8) of the dividend behind the 60 and repeat the process: 608 / 603

Advancing to step 7:
When dividing 608 by 603, we get 1 with a remainder of 5.
The next digit of our result is 1. 
Result so far: 3521.0
Subtract 603 from 608 to get 5.
Append the next digit (6) from the dividend to 5 and continue with: 56 / 603

Advancing to step 8:
When dividing 56 by 603, we get 0 with a remainder of 56.
Write down 0 as next digit of the result. 
Result so far: 35210.0
Subtracting 0 from 56 leaves us with 56.
Since there are no more digits in the dividend, we add a zero to the remainder making it 560, and continue the process.

Moving on to step 9:
603 goes into 560 0 times with a remainder of 560.
The next digit of our result is 0. 
Result so far: 35210.0
Deduct 0 from 560 and we're left with 560.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5600, and continue the process.

Going ahead to step 10:
When dividing 5600 by 603, we get 9 with a remainder of 173.
The number 9 becomes the next digit in our result. 
Result so far: 35210.09
Deduct 5427 from 5600 and we're left with 173.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1730, and continue the process.

Step 11:
If we divide 1730 by 603, we get 2 and a remainder of 524.
Record the quotient 2 as the next digit in the result. 
Result so far: 35210.092
The remainder is 524 after subtracting 1206 from 1730.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5240, and continue the process.

Going ahead to step 12:
603 goes into 5240 8 times with a remainder of 416.
The number 8 becomes the next digit in our result. 
Result so far: 35210.0928
The remainder is 416 after subtracting 4824 from 5240.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4160, and continue the process.

Step 13:
If we divide 4160 by 603, we get 6 and a remainder of 542.
Put 6 as the next digit of the answer. 
Result so far: 35210.09286
If we take 3618 away from 4160, we end up with 542.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5420, and continue the process.

On to step 14:
When dividing 5420 by 603, we get 8 with a remainder of 596.
The number 8 becomes the next digit in our result. 
Result so far: 35210.092868
The remainder is 596 after subtracting 4824 from 5420.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5960, and continue the process.

Going ahead to step 15:
603 goes into 5960 9 times with a remainder of 533.
The number 9 becomes the next digit in our result. 
Result so far: 35210.0928689
If we subtract 5427 from 5960, we get 533.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5330, and continue the process.

Advancing to step 16:
5330 divided by 603 is 8 with a remainder of 506.
Put 8 as the next digit of the answer. 
Result so far: 35210.09286898
Subtract 4824 from 5330 to get 506.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5060, and continue the process.

After the division, we end up with 35210.09286898 and a remainder of 5.06e-07.