1

Ok I see a small issue with the following code:

[CODE]
if cbOperation.items.text = 'add' then

total:=num1+num2;

if cbOperation.items.text = 'subtract' then

total:=num1-num2;

if cbOperation.items.text = 'multiply' then

total:=num1*num2;[/CODE]

it should read as follows:
[CODE]if cbOperation.text = 'add' then

total:=num1+num2;

if cbOperation.text = 'subtract' then

total:=num1-num2;

if cbOperation.text = 'multiply' then

total:=num1*num2;[/CODE]

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].....