Can you find out which number multiplied by itself will give the output as 12345678987654321?

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?

If you were to put a coin into an empty bottle and then insert a cork into the neck, how could you remove the coin without taking out the cork or breaking the bottle?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?

What three numbers, none of which is zero, give the same result whether they’re added or multiplied?

A cat had three kittens: Snophy, Topsy and Jorden. What was the mother's name?

Which part of London exists in France as well ?

What goes up but never comes down?

There is a square of a particular number which when doubled, becomes 7 more than its quarter.

Can you find the number?

A 52% bias toss for head using the 51% tail bias coin was done to obtain a fair result.

Can you find how bias is the floor in this case?