Ok I see a small issue with the following code:
if cbOperation.items.text = 'add' then
if cbOperation.items.text = 'subtract' then
if cbOperation.items.text = 'multiply' then
it should read as follows:
[CODE]if cbOperation.text = 'add' then
if cbOperation.text = 'subtract' then
if cbOperation.text = 'multiply' then
the difference is that I have removed the [CODE].items[/CODE] portion of your code. You dont need it. It wont work
once you have fixed that... another thing you may want to check is that the value you are comparing... for example 'add'... actually does match the value displayed in cbOperation.text
or even do a conversion to uppercase to ensure text values are compariable...
foe example: [CODE]if UpperCase(cbOperation.text) = 'ADD' then[/CODE].....