We look at the division of 402603 by 3 
We want to figure out the number of times 402603 can be divided by 3.

Step 1:
3 goes into 4 1 times with a remainder of 1.
Use 1 as the next digit of our solution. 
Result so far: 1.0
If we take 3 away from 4, we end up with 1.
Grab the next digit (0) from the dividend, add it to 1, then carry on: 10 / 3

Step 2:
3 can be fit into 10 3 times, resulting in a remainder of 1.
The number 3 becomes the next digit in our result. 
Result so far: 13.0
Subtracting 9 from 10 leaves us with 1.
Include the next digit (2) from the dividend after 1, then repeat: 12 / 3

Moving on to step 3:
The number 3 fits into 12 4 times, leaving a remainder of 0.
Write down 4 as next digit of the result. 
Result so far: 134.0
Subtracting 12 from 12 leaves us with 0.
Grab the next digit (6) from the dividend, add it to 0, then carry on: 6 / 3

Advancing to step 4:
If we divide 6 by 3, we get 2 and a remainder of 0.
The number 2 becomes the next digit in our result. 
Result so far: 1342.0
Subtracting 6 from 6 leaves us with 0.
Take the next digit (0) from the dividend and append it to 0, then repeat: 0 / 3

Advancing to step 5:
3 can be fit into 0 0 times, resulting in a remainder of 0.
The next digit of our result is 0. 
Result so far: 13420.0
Deduct 0 from 0 and we're left with 0.
Grab the next digit (3) from the dividend, add it to 0, then carry on: 3 / 3

Let's proceed to step 6:
3 can be fit into 3 1 times, resulting in a remainder of 0.
The number 1 becomes the next digit in our result. 
Result so far: 134201.0
Subtracting 3 from 3 leaves us 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 7:
3 can be fit into 0 0 times, resulting in a remainder of 0.
The next digit of our result is 0. 
Result so far: 134201.0
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.

Step 8:
0 divided by 3 is 0 with a remainder of 0.
The next digit of our result is 0. 
Result so far: 134201.0
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 quotient of the division is 134201.0, and the remainder is 0.0.