I think this is a fool question.....I don't know
Answer:
A.)z+y+x
Step-by-step explanation:
Addition (+) is a commutative operator.
640×3= 1,920 Then you don't need to estimate it since it's estimated.
hope this helps :-)<span />
You find something you can divide the top and bottom number by. You want to get the largest number which in this case is 6. You divide 6 by 6 and 18 by 6 leaving you with 1/3, however if you didn't see that you could also divide both numbers by 3, then continue to simplify.