16666 ÷ 5 = 3333 R1
Alright, let's work through the division of 16666 by 5 step by step.

Step 1:
5 goes into 1 0 times with a remainder of 1.
Write down 0 as next digit of of the result. 
Result so far: 0
Subtract 0 from 1 to get 1.
Bring next digit (6) of the dividend behind the 1 and repeat the process: 16 / 5

Step 2:
5 goes into 16 3 times with a remainder of 1.
Write down 3 as next digit of of the result. 
Result so far: 3
Subtract 15 from 16 to get 1.
Bring next digit (6) of the dividend behind the 1 and repeat the process: 16 / 5

Step 3:
5 goes into 16 3 times with a remainder of 1.
Write down 3 as next digit of of the result. 
Result so far: 33
Subtract 15 from 16 to get 1.
Bring next digit (6) of the dividend behind the 1 and repeat the process: 16 / 5

Step 4:
5 goes into 16 3 times with a remainder of 1.
Write down 3 as next digit of of the result. 
Result so far: 333
Subtract 15 from 16 to get 1.
Bring next digit (6) of the dividend behind the 1 and repeat the process: 16 / 5

Step 5:
5 goes into 16 3 times with a remainder of 1.
Write down 3 as next digit of of the result. 
Result so far: 3333
Subtract 15 from 16 to get 1.

The final result is 3333 with a remainder of 1.