Question

Here a subtraction problem that has been solved incorrectly 21-9=11 what answer I got b 11+9=20​

Answer 1

I put the answer on your copy of this question. However, I can at least put the equation here.

You are correct in this case.

11 + 9 = 20 - 9 = 11

11 plus 9 equals 20, 20 minus 9 equals 11 (correct statement)