 Hi and welcome to the session. Let us discuss the following question. Question says, complete the following statements. Third part is the probability of an event that is certain to happen is dash. Such an event is called dash. Let us now start with the solution. First of all, let us understand what is a sure event. Let us take one example to understand sure event. We know we always get a number less than 7 in a single throw of dice. So getting a number less than 7 is a sure event. So if we are required to find probability of getting a number less than 7 in a single throw of dice is equal to 6 upon 6. Now this is further equal to 1. We know that there are only 6 possible outcomes in a single throw of dice and all outcomes are less than 7. So probability of getting a number less than 7 in a single throw of dice is equal to 6 upon 6 which is equal to 1. Now from above discussion we get probability of sure event is 1. Now we can write the probability of an event that is certain to happen is 1 and such an event is called sure event. Now we can fill in this blank 1 and here we can write sure or certain event. We know sure event is also known as certain event. So this is our required answer. This completes the session. Hope you understood the solution. Take care and keep smiling.