Order of operations

[latifn2]

I had a question about order of operations.

I am given the following data set

X Y
1 2
2 4
4 4
3 2

I must calculate (Summation Sign X)^2 / Summation Sign Y^2

The correct answer is:
(1+2+4+3)^2 / (4+16+16+4)
(10)^2
100/40 = 2.5

I wanted to know why we preform the division operation last when according to BEDMAS, addition is last. Why is the answer not:
100/4+100/16+100/16+100/4 = 62.5

Thanks!

 

[DrPhil]

I had a question about order of operations.

I am given the following data set

X Y
1 2
2 4
4 4
3 2

I must calculate ((Summation Sign X)^2) / (Summation Sign (Y^2))

The correct answer is:
(1+2+4+3)^2 / (4+16+16+4)
(10)^2
100/40 = 2.5

I wanted to know why we preform the division operation last when according to PEDMAS, addition is last. Why is the answer not:
100/4+100/16+100/16+100/4 = 62.5

Thanks!

The Summation operation is like something in parentheses, hence has to be done first. Also, the numerator and the denominator of a fraction should be considered to be in parentheses .. when you write a fraction inline using "/" then you must include the parentheses to maintain the correct order of operations.