166725 ÷ 42 
We want to figure out the number of times 166725 can be divided by 42.

Advancing to step 1:
42 can be fit into 1 0 times, resulting in a remainder of 1.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 1 after subtracting 0 from 1.
Fetch the next digit (6) from the dividend, attach it to 1 and continue: 16 / 42

On to step 2:
The number 42 fits into 16 0 times, leaving a remainder of 16.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 16 after subtracting 0 from 16.
Grab the next digit (6) from the dividend, add it to 16, then carry on: 166 / 42

Going ahead to step 3:
If we divide 166 by 42, we get 3 and a remainder of 40.
Put 3 as the next digit of the answer. 
Result so far: 3.0
Subtract 126 from 166 to get 40.
Bring next digit (7) of the dividend behind the 40 and repeat the process: 407 / 42

Let's proceed to step 4:
If we divide 407 by 42, we get 9 and a remainder of 29.
Write down 9 as next digit of the result. 
Result so far: 39.0
If we subtract 378 from 407, we get 29.
Take the next digit (2) from the dividend and append it to 29, then repeat: 292 / 42

Advancing to step 5:
292 divided by 42 is 6 with a remainder of 40.
Use 6 as the next digit of our solution. 
Result so far: 396.0
If we subtract 252 from 292, we get 40.
Fetch the next digit (5) from the dividend, attach it to 40 and continue: 405 / 42

Let's proceed to step 6:
The number 42 fits into 405 9 times, leaving a remainder of 27.
Put 9 as the next digit of the answer. 
Result so far: 3969.0
Deduct 378 from 405 and we're left with 27.
Since there are no more digits in the dividend, we add a zero to the remainder making it 270, and continue the process.

Let's proceed to step 7:
42 goes into 270 6 times with a remainder of 18.
The number 6 becomes the next digit in our result. 
Result so far: 3969.6
If we take 252 away from 270, we end up with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Moving on to step 8:
When dividing 180 by 42, we get 4 with a remainder of 12.
Put 4 as the next digit of the answer. 
Result so far: 3969.64
If we subtract 168 from 180, we get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

On to step 9:
When dividing 120 by 42, we get 2 with a remainder of 36.
Put 2 as the next digit of the answer. 
Result so far: 3969.642
Deduct 84 from 120 and we're left with 36.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

Step 10:
42 goes into 360 8 times with a remainder of 24.
Record the quotient 8 as the next digit in the result. 
Result so far: 3969.6428
If we subtract 336 from 360, we get 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Let's proceed to step 11:
240 divided by 42 is 5 with a remainder of 30.
Put 5 as the next digit of the answer. 
Result so far: 3969.64285
If we subtract 210 from 240, we get 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Moving on to step 12:
The number 42 fits into 300 7 times, leaving a remainder of 6.
Write down 7 as next digit of the result. 
Result so far: 3969.642857
The remainder is 6 after subtracting 294 from 300.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

On to step 13:
When dividing 60 by 42, we get 1 with a remainder of 18.
Put 1 as the next digit of the answer. 
Result so far: 3969.6428571
If we subtract 42 from 60, we get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Step 14:
42 goes into 180 4 times with a remainder of 12.
The next digit of our result is 4. 
Result so far: 3969.64285714
If we subtract 168 from 180, we get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

The final outcome is 3969.64285714, with a leftover of 1.2e-08.