We're dividing 378487 by 3 
Our goal is to divide 378487 by 3.

Moving on to step 1:
When dividing 3 by 3, we get 1 with a remainder of 0.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Subtract 3 from 3 to get 0.
Bring next digit (7) of the dividend behind the 0 and repeat the process: 7 / 3

Advancing to step 2:
When dividing 7 by 3, we get 2 with a remainder of 1.
The next digit of our result is 2. 
Result so far: 12.0
The remainder is 1 after subtracting 6 from 7.
Grab the next digit (8) from the dividend, add it to 1, then carry on: 18 / 3

Step 3:
3 can be fit into 18 6 times, resulting in a remainder of 0.
Record the quotient 6 as the next digit in the result. 
Result so far: 126.0
Subtracting 18 from 18 leaves us with 0.
Grab the next digit (4) from the dividend, add it to 0, then carry on: 4 / 3

Going ahead to step 4:
3 can be fit into 4 1 times, resulting in a remainder of 1.
Write down 1 as next digit of the result. 
Result so far: 1261.0
If we subtract 3 from 4, we get 1.
Include the next digit (8) from the dividend after 1, then repeat: 18 / 3

Advancing to step 5:
When dividing 18 by 3, we get 6 with a remainder of 0.
Use 6 as the next digit of our solution. 
Result so far: 12616.0
The remainder is 0 after subtracting 18 from 18.
Append the next digit (7) from the dividend to 0 and continue with: 7 / 3

On to step 6:
3 goes into 7 2 times with a remainder of 1.
Write down 2 as next digit of the result. 
Result so far: 126162.0
Subtracting 6 from 7 leaves us with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Advancing to step 7:
10 divided by 3 is 3 with a remainder of 1.
The next digit of our result is 3. 
Result so far: 126162.3
The remainder is 1 after subtracting 9 from 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Going ahead to step 8:
The number 3 fits into 10 3 times, leaving a remainder of 1.
The number 3 becomes the next digit in our result. 
Result so far: 126162.33
Deduct 9 from 10 and we're left with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Our division results in 126162.33 with a remaining 0.001.