Number RiddlesOnline version

A quick number puzzle to test your skills.

by arNas
1

I’m a two-digit number where the tens digit is twice the ones digit and the digits differ by 1.

Hints

The ones digit is 1 and the tens digit is 2, giving 21.

The tens digit is twice the ones digit.

Think of a number between 10 and 99.

2

Many consider me unlucky , but I am special. If you subtract my smaller digit from the higher digit you get the first prime number , and if you add them , you get the first composite number

3

I am an even number , but I am prime.

4

Multiply me by any number from 1 to 10 , and then add up the digits of the product , you will find me again,

5

if you add me before a number , the number doe not change ,but if you add me after a number ,it becomes much bigger,