Let's divide 20138170 by 129
We're looking to find how many times 129 goes into 20138170.

On to step 1:
If we divide 2 by 129, we get 0 and a remainder of 2.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 2 after subtracting 0 from 2.
Bring next digit (0) of the dividend behind the 2 and repeat the process: 20 / 129

On to step 2:
129 can be fit into 20 0 times, resulting in a remainder of 20.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 20 and we're left with 20.
Fetch the next digit (1) from the dividend, attach it to 20 and continue: 201 / 129

On to step 3:
The number 129 fits into 201 1 times, leaving a remainder of 72.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
If we take 129 away from 201, we end up with 72.
Fetch the next digit (3) from the dividend, attach it to 72 and continue: 723 / 129

On to step 4:
When dividing 723 by 129, we get 5 with a remainder of 78.
Write down 5 as next digit of the result. 
Result so far: 15.0
Deduct 645 from 723 and we're left with 78.
Bring next digit (8) of the dividend behind the 78 and repeat the process: 788 / 129

On to step 5:
The number 129 fits into 788 6 times, leaving a remainder of 14.
The number 6 becomes the next digit in our result. 
Result so far: 156.0
If we subtract 774 from 788, we get 14.
Append the next digit (1) from the dividend to 14 and continue with: 141 / 129

Advancing to step 6:
When dividing 141 by 129, we get 1 with a remainder of 12.
Use 1 as the next digit of our solution. 
Result so far: 1561.0
If we subtract 129 from 141, we get 12.
Grab the next digit (7) from the dividend, add it to 12, then carry on: 127 / 129

Going ahead to step 7:
129 can be fit into 127 0 times, resulting in a remainder of 127.
Put 0 as the next digit of the answer. 
Result so far: 15610.0
Deduct 0 from 127 and we're left with 127.
Bring next digit (0) of the dividend behind the 127 and repeat the process: 1270 / 129

On to step 8:
The number 129 fits into 1270 9 times, leaving a remainder of 109.
Record the quotient 9 as the next digit in the result. 
Result so far: 156109.0
Deduct 1161 from 1270 and we're left with 109.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1090, and continue the process.

Let's proceed to step 9:
129 can be fit into 1090 8 times, resulting in a remainder of 58.
The next digit of our result is 8. 
Result so far: 156109.8
If we take 1032 away from 1090, we end up with 58.
Since there are no more digits in the dividend, we add a zero to the remainder making it 580, and continue the process.

Going ahead to step 10:
129 goes into 580 4 times with a remainder of 64.
Write down 4 as next digit of the result. 
Result so far: 156109.84
Deduct 516 from 580 and we're left with 64.
Since there are no more digits in the dividend, we add a zero to the remainder making it 640, and continue the process.

Step 11:
The number 129 fits into 640 4 times, leaving a remainder of 124.
Record the quotient 4 as the next digit in the result. 
Result so far: 156109.844
Deduct 516 from 640 and we're left with 124.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1240, and continue the process.

The final outcome is 156109.844, with a leftover of 0.0124.