Well, this is a slightly different sum that involves one more four. Are you sure that you wrote the problem down correctly? It involves both mathematical addition (denoted by normal brackets) and addition of characters [denoted by square brackets].
[4 + 4] = 44
(4 + 5) = 9
[44 + 9] = 449
Or in one step, [[4 + 4] + (4 + 5)] = 449
the answer to that is 5
Commutative
8 + 5 + 4 = 17
5. Just do 9 minus 4. 5 plus 4 equals 9
19
7+2+5= 14 35 42
the answer to that is 5
true
Commutative
27
8 + 5 + 4 = 17
5. Just do 9 minus 4. 5 plus 4 equals 9
No.
false
yes
19
20