For the ‘Any Card at Any Number’ lovers, Cards and Numbers will most certainly be something you’ll want to add to your arsenal! The spectator can cut the deck as many times as they like, box the cards, and put them in their purse or sit on them. They then go through a quick imaginary process, where the spectator selects a truly random card and random number. With no forcing involved, and the performer never needing to touch the deck, the spectator can remove the cards, count to whatever number they chose, and find the card they selected!
To be forward, there is a stack. But it can be any stack that you know or are familiar with! Si Stebbins, Breakthrough, or any other would work perfectly fine with this concept. Aside from knowing your stack, no sleights are involved and no mathematics are needed. In fact, you do very little.