I have a multi-select text field parsing

Is the multi-line text field the best way to capture/store this information?  Are you able to use multi-select text fields, which are more easily referenced in formulas.  Can you leverage a table of products associated to a record?  Can you use checkboxes to represent products? 

Are your "products" the only content of the multi-line text field separated by semi-colons?

yes... just to specify it is a summary multi-select text field

[Report Items 1] is my multi-select text field.  You will need to replace the formula with yours.

var number one=If(Part(ToText([Report Items 1]),1,";")<>"",1,0);
var number two=If(Part(ToText([Report Items 1]),2,";")<>"",1,0);
var number three=If(Part(ToText([Report Items 1]),3,";")<>"",1,0);
var number four=If(Part(ToText([Report Items 1]),4,";")<>"",1,0);
var number five=If(Part(ToText([Report Items 1]),5,";")<>"",1,0);
var number six=If(Part(ToText([Report Items 1]),6,";")<>"",1,0);
var number seven=If(Part(ToText([Report Items 1]),7,";")<>"",1,0);
var number eight=If(Part(ToText([Report Items 1]),8,";")<>"",1,0);
var number nine=If(Part(ToText([Report Items 1]),9,";")<>"",1,0);
var number ten=If(Part(ToText([Report Items 1]),10,";")<>"",1,0);
var number eleven=If(Part(ToText([Report Items 1]),11,";")<>"",1,0);
var number twelve=If(Part(ToText([Report Items 1]),12,";")<>"",1,0);
var number thirteen=If(Part(ToText([Report Items 1]),13,";")<>"",1,0);
var number fourteen=If(Part(ToText([Report Items 1]),14,";")<>"",1,0);
var number fifteen=If(Part(ToText([Report Items 1]),15,";")<>"",1,0);
var number sixteen=If(Part(ToText([Report Items 1]),16,";")<>"",1,0);
var number seventeen=If(Part(ToText([Report Items 1]),17,";")<>"",1,0);
var number eighteen=If(Part(ToText([Report Items 1]),18,";")<>"",1,0);
var number nineteen=If(Part(ToText([Report Items 1]),19,";")<>"",1,0);
var number twenty=If(Part(ToText([Report Items 1]),20,";")<>"",1,0);

var number sum=Sum($one,$two,$three,$four,$five,$six,$seven,$eight,$nine,$ten,$eleven,$twelve,$thirteen,$fourteen,$fifteen,$sixteen,$seventeen,$eighteen,$nineteen,$twenty);

$sum

I am getting this error? Is it because it is a summary field from another table?

When I do the formula on the summary combined text field; even though it gives me an error, the formula still works

Thanks. That was fruitful.