How to immediately abort a calculation?

[hqvrrsc4]

Well I bought an hp prime several days ago. And I found that... Some integrals/equations will cause the calculator to hang up with a little hourglass icon on the corner of the screen. -This is understandable. But how could I abort the calculation if I don't want it to go on? Now I can only reset the calculator by inserting a paper clip into the reset hole on the back of the calculator. But I don't want to bring a paper clip everywhere with me. Is there any "easier" way achieving this?

Edit: After smashing the keyboard for a while, I found thant hitting "Symb" + "On" will immediately shut down the calculator. But it will clear all history since last boot up. Is there a better solution, which behaviors like hitting "ctrl+C" in matlab(just abort the current calculation and nothing more)?