42166560 ÷ 398 
We want to figure out the number of times 42166560 can be divided by 398.

Let's proceed to step 1:
If we divide 4 by 398, we get 0 and a remainder of 4.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 4 after subtracting 0 from 4.
Append the next digit (2) from the dividend to 4 and continue with: 42 / 398

Going ahead to step 2:
398 goes into 42 0 times with a remainder of 42.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 42 to get 42.
Bring next digit (1) of the dividend behind the 42 and repeat the process: 421 / 398

Going ahead to step 3:
421 divided by 398 is 1 with a remainder of 23.
Write down 1 as next digit of the result. 
Result so far: 1.0
Subtract 398 from 421 to get 23.
Bring next digit (6) of the dividend behind the 23 and repeat the process: 236 / 398

Step 4:
398 goes into 236 0 times with a remainder of 236.
The number 0 becomes the next digit in our result. 
Result so far: 10.0
Subtracting 0 from 236 leaves us with 236.
Include the next digit (6) from the dividend after 236, then repeat: 2366 / 398

On to step 5:
When dividing 2366 by 398, we get 5 with a remainder of 376.
Use 5 as the next digit of our solution. 
Result so far: 105.0
The remainder is 376 after subtracting 1990 from 2366.
Bring next digit (5) of the dividend behind the 376 and repeat the process: 3765 / 398

Step 6:
398 can be fit into 3765 9 times, resulting in a remainder of 183.
Write down 9 as next digit of the result. 
Result so far: 1059.0
Subtracting 3582 from 3765 leaves us with 183.
Append the next digit (6) from the dividend to 183 and continue with: 1836 / 398

Going ahead to step 7:
1836 divided by 398 is 4 with a remainder of 244.
Record the quotient 4 as the next digit in the result. 
Result so far: 10594.0
The remainder is 244 after subtracting 1592 from 1836.
Grab the next digit (0) from the dividend, add it to 244, then carry on: 2440 / 398

Going ahead to step 8:
398 goes into 2440 6 times with a remainder of 52.
The number 6 becomes the next digit in our result. 
Result so far: 105946.0
Subtracting 2388 from 2440 leaves us with 52.
Since there are no more digits in the dividend, we add a zero to the remainder making it 520, and continue the process.

Advancing to step 9:
The number 398 fits into 520 1 times, leaving a remainder of 122.
The next digit of our result is 1. 
Result so far: 105946.1
If we take 398 away from 520, we end up with 122.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1220, and continue the process.

Going ahead to step 10:
If we divide 1220 by 398, we get 3 and a remainder of 26.
Put 3 as the next digit of the answer. 
Result so far: 105946.13
Subtracting 1194 from 1220 leaves us with 26.
Since there are no more digits in the dividend, we add a zero to the remainder making it 260, and continue the process.

Going ahead to step 11:
260 divided by 398 is 0 with a remainder of 260.
Use 0 as the next digit of our solution. 
Result so far: 105946.13
If we take 0 away from 260, we end up with 260.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2600, and continue the process.

Let's proceed to step 12:
398 can be fit into 2600 6 times, resulting in a remainder of 212.
The number 6 becomes the next digit in our result. 
Result so far: 105946.1306
The remainder is 212 after subtracting 2388 from 2600.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2120, and continue the process.

Step 13:
If we divide 2120 by 398, we get 5 and a remainder of 130.
Write down 5 as next digit of the result. 
Result so far: 105946.13065
The remainder is 130 after subtracting 1990 from 2120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1300, and continue the process.

Step 14:
398 goes into 1300 3 times with a remainder of 106.
Use 3 as the next digit of our solution. 
Result so far: 105946.130653
If we subtract 1194 from 1300, we get 106.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1060, and continue the process.

Moving on to step 15:
398 can be fit into 1060 2 times, resulting in a remainder of 264.
The number 2 becomes the next digit in our result. 
Result so far: 105946.1306532
If we subtract 796 from 1060, we get 264.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2640, and continue the process.

Let's proceed to step 16:
The number 398 fits into 2640 6 times, leaving a remainder of 252.
The number 6 becomes the next digit in our result. 
Result so far: 105946.13065326
Subtract 2388 from 2640 to get 252.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2520, and continue the process.

Our division results in 105946.13065326 with a remaining 2.52e-07.