665 ÷ 4 = 166 R1
Alright, let's work through the division of 665 by 4 step by step.

Step 1:
4 goes into 6 1 times with a remainder of 2.
Write down 1 as next digit of of the result. 
Result so far: 1
Subtract 4 from 6 to get 2.
Bring next digit (6) of the dividend behind the 2 and repeat the process: 26 / 4

Step 2:
4 goes into 26 6 times with a remainder of 2.
Write down 6 as next digit of of the result. 
Result so far: 16
Subtract 24 from 26 to get 2.
Bring next digit (5) of the dividend behind the 2 and repeat the process: 25 / 4

Step 3:
4 goes into 25 6 times with a remainder of 1.
Write down 6 as next digit of of the result. 
Result so far: 166
Subtract 24 from 25 to get 1.

The final result is 166 with a remainder of 1.