TwentyFour

FOUR CARDS, ONE TARGET

Four cards. Use each one exactly once with + − × ÷ to make 24. Clear the deck as fast as you can. 

Drag a card onto another and a wheel of + − × ÷ appears, then let go on the one you want. The two become one card holding the result. The dragged card goes on the left, so 7 onto 3 is 7 − 3.

Undo and Reset are free. Give up costs 120s and shows an answer: every hand has one.