Step by step
The question
Question: A card is picked from a deck of 52 cards.
What is the probability it is a heart?
The probability is a fraction: the outcomes we want, over all the outcomes.
P stands for probability.
1 Count all outcomes
A deck has 52 cards.
It has 4 suits: hearts, diamonds, clubs and spades.
Each suit has 13 cards.
4 times 13 is 52.
2 Count the ones we want
Hearts: 13.
That is 13 outcomes we want.
3 Write the fraction
13 we want, out of 52.
So the probability is 13/52.
Careful!
The bottom is all the outcomes, 52.
Not only the other 39.
4 Simplify
Both 13 and 52 can be divided by 13.
That makes it simpler.
So it is 1/4.
5 As a percent
Percent means out of 100.
We make the bottom 100: times 25, top and bottom.
25 out of 100 is 25%.
6 Check
Let's check with the others.
52 minus 13 is 39.
13/52 plus 39/52 is 52/52: that is 1, all of them.
So the answer is right!
Let's look back.
First: count all outcomes.
Then: count the ones we want.
Then: write the fraction.
Then: simplify.
Then: as a percent.
Last: check.