What percent of 84 is 21

Dylan is evaluation the expression 13+19+7+10 at one step in his work, dylan rewrites the equation as 13+7+19+10 which property of addition must dylan have used when he evaluated the expression?

Select quivalent or not equivalent to indicate whether the expression above is equivalent or not equivalent to the values or expressions in the last column.

Of the 50 us states 4 have names that start with the letter w