Probability is the branch of mathematics concerning numerical descriptions of how likely an event is to occur, or how likely it is that a proposition is true. The probability of an event is a number between 0 and 1, where, roughly speaking, 0 indicates impossibility of the event and 1 indicates certainty.
Experimental probability is the results of an experiment, let's say for the sake of an example marbles in a bag. Experimental probability would be drawing marbles out of the bag and recording the results. Theoretical probability is calculating the probability of it happening, not actually going out and experimenting.
These math worksheets should be practiced regularly and are free to download in PDF formats.
Theoretical and Experimental Probability Worksheet - 1
Theoretical and Experimental Probability Worksheet - 2
Theoretical and Experimental Probability Worksheet - 3
Theoretical and Experimental Probability Worksheet - 4