I have mixed feelings about mine.. I tried clicking in the numbers at first but it wouldn't register some numbers if I went too fast, but I ended up just using the 10-key pad on the right side of the keyboard and it worked like a charm! (PHEW).
yes mine was very responsive and worked fine! only one small problem i think you have to click equals every damn time instead of just clicking the next operation. You can also type on your keyboard numpad as well which helped save me TONS of time. I realized this only halfway through QR 😕