1866 ÷ 9 = 207 R3
We're going to perform division on 1866 with 9 as the divisor.

Step 1:
9 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 (8) of the dividend behind the 1 and repeat the process: 18 / 9

Step 2:
9 goes into 18 2 times with a remainder of 0.
Write down 2 as next digit of of the result. 
Result so far: 2
Subtract 18 from 18 to get 0.
Bring next digit (6) of the dividend behind the 0 and repeat the process: 6 / 9

Step 3:
9 goes into 6 0 times with a remainder of 6.
Write down 0 as next digit of of the result. 
Result so far: 20
Subtract 0 from 6 to get 6.
Bring next digit (6) of the dividend behind the 6 and repeat the process: 66 / 9

Step 4:
9 goes into 66 7 times with a remainder of 3.
Write down 7 as next digit of of the result. 
Result so far: 207
Subtract 63 from 66 to get 3.

The final result is 207 with a remainder of 3.