 Dividing 99999999 by 1, which is the worst case for the simple long division method used on many calculators, takes roughly 200 milliseconds, and addition and subtraction are nearly instantaneous.The QT-8D is much smaller than earlier calculators; it is about long, wide, and high, and it weighs about .Although it isn't truly portable, since it needs AC power to operate, it does have a carrying handle on the rear, allowing it to be moved around easily.