One solution for various input

There's nothing wrong with the calculations.

0.3/30 = 0.2/20 = 0.1/10.

You should be aware that the origin for indexing vectors and matrices is set by default to 0.That's why you get 0 as the first element of the vector LPM.

Type

 ORIGIN =

anywhere on the sheet to see that it's value is 0. You can alternatively assign it the value 1 with:

 ORIGIN : 1

which displays as

 ORIGIN := 1

and to the right of, and below this definition ORIGIN will be 1.

In your summation you've used the indexes 1 through 3, which sums all three quotients into LPM.

Subsequently you defined LPM[1 (the second element of the vector LPM) as the 'first' quotient. This redefines LPM (the sum) to a new variable, which is now a vector. Then you assigned the third element of that vector as well, with the second quotient. Upon displaying the value of the vector LPM, with:

LPM=

you are presented with the 3-element array.

Your calculations could be:

without worrying about the value of ORIGIN...

Success!
Luc