Replace the question mark with the correct number below.

Double it and multiply it by 4. Then divide it by 8 and you’ll have it once more. What number is it?

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?

I went to the bookshop and spent one-half of the money that was in my purse.

When I came out, I found that I had as many cents as I had dollars and half as many dollars as I had cents when I went in. Find the money in my purse when I entered the store.

Get total of 120 by using five zeros 0,0,0,0,0 and any one mathematical operator.
Do you ?

Find the next number in the sequence

5 12 24 36 ?

On my way to St. Ives I saw a man with 7 wives. Each wife had 7 sacks. Each sack had 7 cats. Each cat had 7 kittens. Kittens, cats, sacks, wives. How many were going to St. Ives?

What is more useful when it is broken?

Can you calculate the probability of getting a sum of six when a dice is thrown twice?

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?