639971 ÷ 42 
We're looking to find how many times 42 goes into 639971.

On to step 1:
42 goes into 6 0 times with a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Grab the next digit (3) from the dividend, add it to 6, then carry on: 63 / 42

Moving on to step 2:
The number 42 fits into 63 1 times, leaving a remainder of 21.
The next digit of our result is 1. 
Result so far: 1.0
The remainder is 21 after subtracting 42 from 63.
Grab the next digit (9) from the dividend, add it to 21, then carry on: 219 / 42

Let's proceed to step 3:
If we divide 219 by 42, we get 5 and a remainder of 9.
Use 5 as the next digit of our solution. 
Result so far: 15.0
The remainder is 9 after subtracting 210 from 219.
Fetch the next digit (9) from the dividend, attach it to 9 and continue: 99 / 42

Advancing to step 4:
If we divide 99 by 42, we get 2 and a remainder of 15.
Record the quotient 2 as the next digit in the result. 
Result so far: 152.0
Deduct 84 from 99 and we're left with 15.
Grab the next digit (7) from the dividend, add it to 15, then carry on: 157 / 42

Moving on to step 5:
157 divided by 42 is 3 with a remainder of 31.
Use 3 as the next digit of our solution. 
Result so far: 1523.0
If we subtract 126 from 157, we get 31.
Include the next digit (1) from the dividend after 31, then repeat: 311 / 42

Moving on to step 6:
The number 42 fits into 311 7 times, leaving a remainder of 17.
Write down 7 as next digit of the result. 
Result so far: 15237.0
Subtract 294 from 311 to get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Step 7:
When dividing 170 by 42, we get 4 with a remainder of 2.
Put 4 as the next digit of the answer. 
Result so far: 15237.4
Subtract 168 from 170 to get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Moving on to step 8:
42 can be fit into 20 0 times, resulting in a remainder of 20.
The next digit of our result is 0. 
Result so far: 15237.4
If we take 0 away from 20, we end up with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Moving on to step 9:
When dividing 200 by 42, we get 4 with a remainder of 32.
Record the quotient 4 as the next digit in the result. 
Result so far: 15237.404
Subtract 168 from 200 to get 32.
Since there are no more digits in the dividend, we add a zero to the remainder making it 320, and continue the process.

On to step 10:
The number 42 fits into 320 7 times, leaving a remainder of 26.
The next digit of our result is 7. 
Result so far: 15237.4047
Deduct 294 from 320 and we're left 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.

Advancing to step 11:
The number 42 fits into 260 6 times, leaving a remainder of 8.
The number 6 becomes the next digit in our result. 
Result so far: 15237.40476
Deduct 252 from 260 and we're left with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Going ahead to step 12:
80 divided by 42 is 1 with a remainder of 38.
The next digit of our result is 1. 
Result so far: 15237.404761
If we subtract 42 from 80, we get 38.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

Going ahead to step 13:
The number 42 fits into 380 9 times, leaving a remainder of 2.
Record the quotient 9 as the next digit in the result. 
Result so far: 15237.4047619
Subtract 378 from 380 to get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Going ahead to step 14:
20 divided by 42 is 0 with a remainder of 20.
The next digit of our result is 0. 
Result so far: 15237.4047619
Deduct 0 from 20 and we're left with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

In conclusion, the division gives 15237.4047619 with a balance of 2e-08.