39142 ÷ 3 = 13047 R1
Let's divide 39142 by 3.

Step 1:
3 goes into 3 1 times with a remainder of 0.
Write down 1 as next digit of of the result. 
Result so far: 1
Subtract 3 from 3 to get 0.
Bring next digit (9) of the dividend behind the 0 and repeat the process: 9 / 3

Step 2:
3 goes into 9 3 times with a remainder of 0.
Write down 3 as next digit of of the result. 
Result so far: 13
Subtract 9 from 9 to get 0.
Bring next digit (1) of the dividend behind the 0 and repeat the process: 1 / 3

Step 3:
3 goes into 1 0 times with a remainder of 1.
Write down 0 as next digit of of the result. 
Result so far: 130
Subtract 0 from 1 to get 1.
Bring next digit (4) of the dividend behind the 1 and repeat the process: 14 / 3

Step 4:
3 goes into 14 4 times with a remainder of 2.
Write down 4 as next digit of of the result. 
Result so far: 1304
Subtract 12 from 14 to get 2.
Bring next digit (2) of the dividend behind the 2 and repeat the process: 22 / 3

Step 5:
3 goes into 22 7 times with a remainder of 1.
Write down 7 as next digit of of the result. 
Result so far: 13047
Subtract 21 from 22 to get 1.

The final result is 13047 with a remainder of 1.