2050s and 2060s, though it will NOT be the same.
Xy + 3z (Use any numbers you want for the variables. Lets say X=2, Y=5, Z=3)
2x5 + 3x3
10 + 3x3 (2x5=10)
10 + 9 (3x3=9)
19 (10+9=19)
So if you were to use the commutative property, you would write
2x5 + 3x3=3x3 + 2x5