Hello there!
If a bag has 12 balls labelled 1 through 12, that means that the balls inside the bag includes:
1 2 3 4 5 6 7 8 9 10 11 12
When creating a fraction for a probability, the numerator usually consists of a specific probability you are trying to find; the denominator usually consists of the total amount of samples in the bag.
In this example: What is the probability of picking an even number?
Ask yourself: What are we trying to find?
We are trying to find the probability of even numbers.
Then ask yourself: What is the amount of possibilities that we can get an even number from the bag?
The bag consists of: 1 2 3 4 5 6 7 8 9 10 11 12
Even numbers are divisible by 2 and has a remainder of 0 ; which means in this bag, the bolded numbers are even.
Then we can conclude that in this bag, counting all of the bolded numbers, we have 6 possibilities of choosing an even number.
Finally, think about: What is the total amount of samples in this bag?
We know that there are 12 balls, so 12 would be the total amount.
To conclude, we can find 6 even numbers in a bag of 12 balls;
Therefore, the chances you can pick an even number is
or
.