10999 ÷ 3 = 3666 R1
We're going to perform division on 10999 with 3 as the divisor.

Step 1:
3 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 (0) of the dividend behind the 1 and repeat the process: 10 / 3

Step 2:
3 goes into 10 3 times with a remainder of 1.
Write down 3 as next digit of of the result. 
Result so far: 3
Subtract 9 from 10 to get 1.
Bring next digit (9) of the dividend behind the 1 and repeat the process: 19 / 3

Step 3:
3 goes into 19 6 times with a remainder of 1.
Write down 6 as next digit of of the result. 
Result so far: 36
Subtract 18 from 19 to get 1.
Bring next digit (9) of the dividend behind the 1 and repeat the process: 19 / 3

Step 4:
3 goes into 19 6 times with a remainder of 1.
Write down 6 as next digit of of the result. 
Result so far: 366
Subtract 18 from 19 to get 1.
Bring next digit (9) of the dividend behind the 1 and repeat the process: 19 / 3

Step 5:
3 goes into 19 6 times with a remainder of 1.
Write down 6 as next digit of of the result. 
Result so far: 3666
Subtract 18 from 19 to get 1.

The final result is 3666 with a remainder of 1.