What does below rebus means ?

In a mathematical quiz, you are asked the following question:

Use three 9s in a mathematical expression without dividing or multiplying to form the number one.

Can you answer the question?

Take away the whole and some still remain. What is it?

What does the below rebus riddle means?

Five teams were competing in cricket where they faced each other exactly once. After the tournament, the following is the point table.

DareDevils 6
SuperKings 5
Royals 4
Sunrisers 2
Riders ?

How many points did Riders end up with?

We know that the number 7 is the prime followed by a cube. Which next number is also a prime followed by a cube?

Joseph buys three kinds of chocolates for 100 rupees. The first one is priced at 5 rupees, second one at 3 rupees and third one at 0.5 rupees.

If he bought 100 chocolates in total, how many pieces do you think he bought each chocolate?

In a science lab, a petri dish hosts a healthy colony of yeast for an experiment. Now every minute, all the yeast cells divide into two. At noon, there was just a single cell of yeast and at 1:22, the Petri dish was half full. Can you calculate when the dish will be full of yeast?

Can you replace the X (both small and big x) with the numbers between 1 to 19 such that all the rows of 3 numbers between X (big x) sum to 23?

My thunder comes before the lightning; my lightning comes before clouds; my rain dries all the land it touches. What am I?