If I roll two regular six-sided dice, what’s the probability of getting a sum that’s a prime number?

Question

If you have an answer, how did you get it? Or explain.

Answer 1

You have 36 possible outcomes... Make a list to show them.

1 1

1 2

1 3

.

.

.

6 3

6 4

6 5

6 6

 

Then make a 3rd column to the right for the sum...

1 1  2

1  2 3

1. 3 .4

.

.

.

6 4  10

6 5. 11

6 6 12

 

Now go to the right and make a 4th column to make a check mark beside the ones that are prime.

 

Finally, count the number of check marks and divide by 36.