We're dividing 420860 by 3 
We're looking to find how many times 3 goes into 420860.

Let's proceed to step 1:
3 can be fit into 4 1 times, resulting in a remainder of 1.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
If we take 3 away from 4, we end up with 1.
Grab the next digit (2) from the dividend, add it to 1, then carry on: 12 / 3

Step 2:
If we divide 12 by 3, we get 4 and a remainder of 0.
Put 4 as the next digit of the answer. 
Result so far: 14.0
If we subtract 12 from 12, we get 0.
Take the next digit (0) from the dividend and append it to 0, then repeat: 0 / 3

On to step 3:
3 can be fit into 0 0 times, resulting in a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 140.0
The remainder is 0 after subtracting 0 from 0.
Fetch the next digit (8) from the dividend, attach it to 0 and continue: 8 / 3

Let's proceed to step 4:
The number 3 fits into 8 2 times, leaving a remainder of 2.
The number 2 becomes the next digit in our result. 
Result so far: 1402.0
Subtracting 6 from 8 leaves us with 2.
Append the next digit (6) from the dividend to 2 and continue with: 26 / 3

Moving on to step 5:
3 goes into 26 8 times with a remainder of 2.
Put 8 as the next digit of the answer. 
Result so far: 14028.0
If we subtract 24 from 26, we get 2.
Include the next digit (0) from the dividend after 2, then repeat: 20 / 3

Let's proceed to step 6:
If we divide 20 by 3, we get 6 and a remainder of 2.
The number 6 becomes the next digit in our result. 
Result so far: 140286.0
If we subtract 18 from 20, we get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Advancing to step 7:
When dividing 20 by 3, we get 6 with a remainder of 2.
The next digit of our result is 6. 
Result so far: 140286.6
Deduct 18 from 20 and we're left with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

On to step 8:
3 can be fit into 20 6 times, resulting in a remainder of 2.
Put 6 as the next digit of the answer. 
Result so far: 140286.66
Subtract 18 from 20 to get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

The quotient of the division is 140286.66, and the remainder is 0.002.