There are 52 cards in 1 deck.
the least is 1, and the greatest is 13
4 of those cards are "6"
6/52 = 0.1153, or 11.53% (not rounded)
1/4 of the cards are hearts (as the suites are hearts, diamonds, clover, and spades.
Divide 4 from 52
52/4 = 13
The chance of getting a heart is 13/52 = 0.25, or 25% chance
hope this helps