Three cards add up to 9, 19, 29, and finally there is one left. What do hearts, diamonds, spades and clubs mean?

According to the topic, we need to calculate the sum of three cards to get 9, 19, 29, and finally get a 3.

The first card is 9, and the rest are -6.

The second card is: 19, leaving:-16.

The third card is: 29, leaving: -26.

So, 3 of hearts stands for the first card, that is, the card whose three cards add up to 9.

The third box represents the second card, that is, the card whose three cards add up to 19.

Spades 3 stands for the third card, that is, the card whose three cards add up to 29.

Club 3 represents the remaining cards, that is, the remaining cards.