First things first, an informal definition of probability would be chance, rather a one word answer for it. Intentionally or unintentionally, we have all used probability at least once in our life.  The most common one would be, “Would it rain today?” there can only be two chances, either yes or no. Another common example would be, a coin toss example, where one might bet that if head appears he/she wins, if tail appears he/she will lose. This might look very easy and might not even excite the grey matter at all. Probability is a lot more than a simple coin toss. Every subject or chapter that is being taught is for some purpose, this is where probability excels, it can be said that probabilityrevolutionized the subject Statistics. Though, predominantly it is an integral part of Mathematics, probability is like a vital cog to the machine (statistics).
            In class 10, probability can be looked upon as a scoring chapter. The basics of probabilityshould be well defined to the students and the students themselves should be well versed. The key to understanding probabilityis, to learn the basics. I would like to demonstrate it using a suitable example.
Example: A fair coin is tossed i.e. not a biased coin; If head appears then it will be denoted as success, if tail appears it will denoted as failure.
Here, there are two chances; either it will be a head or a tail. Therefore, the sample space here would be 2 i.e. the possible number of outcomes. Now, let us denote an event A, which we would categorize as success, then the probability of success in a single coin toss can be written as:  Head appears in a single coin toss  =1/2
                                                           Total number of outcomes
Hence, it can be seen that the answer would be ½ or 0.5. Conventionally probability of a certain event is denoted by p.
A briefed idea about probability can make one thing that this subject is monotonous. Once dived into depth, this chapter unfolds into numerous branches of uses and ideas.
In class 10, the depth of the chapter cannot be understood still, the base of the chapter will be made very clear to you and you might find it intriguing as well.