I agree with Kym, you have to enter the correct sequence to tell it wat to do. Try the same expression with the Windows calculator and you will get 1 + 2 * 3 = 9. Is Microsoft wrong too ?

All of you are right & wrong at the same time. The rule of math depends on what you are calculating eg. (1+2)*3=9 or 1+(2*3)=7. Even in computer you have to enter the correct sequence to tell it wat to do. Do you want the sum to be multiply by 3 or do you want the sum to be add to 1? If you pay attention in Math class you should have learn this basic instruction. Jorge did a good job with this widget as it did wat a normal, simple calculator should do. If you people want a scientific calculation then write one yourself.

I agree with Simon and Xenedar: a good calculator should follow the rules of mathematics. Otherwise, how do you divine if the end calculation is correct? I'm afraid maths is not a matter of opinion.
It's disappointing, since the widget itself is so nice.

Just what I was looking for.

Very nice... well done!