223
- 1 1 9
---------- so combine just means you going to take two numbers to subtract. So since 3 is small then 9 your going to use combine which is taking 19 from 23 so count back 20 21 22 23 so you counted back 4 spaces so you put 4 under the 9 you had no tens so you put a zero under the1 the now you just subtract2-1=1 so your answer is 109 that is called combine place value