We look at the division of 138503 by 1 
We want to divide 138503 by 1.

On to step 1:
1 goes into 1 1 times with a remainder of 0.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
Deduct 1 from 1 and we're left with 0.
Bring next digit (3) of the dividend behind the 0 and repeat the process: 3 / 1

Moving on to step 2:
1 goes into 3 3 times with a remainder of 0.
Put 3 as the next digit of the answer. 
Result so far: 13.0
If we take 3 away from 3, we end up with 0.
Grab the next digit (8) from the dividend, add it to 0, then carry on: 8 / 1

On to step 3:
1 can be fit into 8 8 times, resulting in a remainder of 0.
Record the quotient 8 as the next digit in the result. 
Result so far: 138.0
The remainder is 0 after subtracting 8 from 8.
Include the next digit (5) from the dividend after 0, then repeat: 5 / 1

Moving on to step 4:
1 can be fit into 5 5 times, resulting in a remainder of 0.
Record the quotient 5 as the next digit in the result. 
Result so far: 1385.0
Deduct 5 from 5 and we're left with 0.
Bring next digit (0) of the dividend behind the 0 and repeat the process: 0 / 1

Moving on to step 5:
If we divide 0 by 1, we get 0 and a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 13850.0
If we subtract 0 from 0, we get 0.
Bring next digit (3) of the dividend behind the 0 and repeat the process: 3 / 1

On to step 6:
1 can be fit into 3 3 times, resulting in a remainder of 0.
Put 3 as the next digit of the answer. 
Result so far: 138503.0
The remainder is 0 after subtracting 3 from 3.
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:
The number 1 fits into 0 0 times, leaving a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 138503.0
If we subtract 0 from 0, we 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.

On to step 8:
1 goes into 0 0 times with a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 138503.0
The remainder is 0 after subtracting 0 from 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Our division results in 138503.0 with a remaining 0.0.