The commutative property will be like : a + b = b + a or like A * B = B * A
So, we will check the given :
21. 5 + 6 = 6 +5 [yes]
22. 9 - 2 = 2 - 9 [No]
23. (3)(4) = (4)(3) [yes]
24. 8 ÷ 4 = 4 ÷ 8 [No]
25. 2m + 7 = 7 + 2m [yes]
26. 5g - 13 = 13 - 5g [No]
27. 9 - n = n - 9 [No]
28. 4 + x = x + 4 [yes]
as you see it is yes in case of sum and multiply
And no in case of subtract and divide