What is the probability of rolling a pair of dice and not rolling the same number?

5/6

Step-by-step explanation:

The "first" dice can land on any number, so there are 6 choices. The "second" can not be the same number as the first one. So there are 5 choices. We multiply to get 6*5=30 ways to roll a different number. There are 6*6 total ways so the probability is 30/36 which simplifies to 5/6.

he spend 5.1 minutes chatting with his friends.

step-by-step explanation:

2/5+1/2=9/10

6/1-9/10=5.1