Given 3 numbers A, B and C, for a commutative property
(A+B)+C = C+(A+B)
This shows that the remains the same no matter what values comes first
For the given expression
4/5+6.9y-8 = 6.9y+8-4.5
The values are not commutative because of the presence of negative sign. For the expression to be commutative, they must be equal no matter the way it is arranged and the sign must be positive all through for both sides. Hence Maggie did not apply the law correctly
