Maths Logic

Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10




Similar Riddles

Move three sticks of the spiral below to form a square.

Spiral to Square Puzzle

Asked by Neha on 15 Nov 2025


There was a kingdom in which the king had no heir to take over his thrown. Even the queen was dead and he himself was on the verge of dying. He thought about it and then summoned all of the teenagers. He gave one seed each to all of them and asked them to grow the plant. He announced that the one with the most beautiful plant will become the king/queen of the empire after the death of the king.

After a month, all of them were called. The king looked at all of the plants but announced the girl with an empty pot as the queen of the empire. Why?

Asked by Neha on 24 Sep 2024

Two batsman each on 94 runs. Seven runs needed to win in last 3 balls. Both make 100*. How?

Asked by Neha on 05 Feb 2023


I can sizzle like bacon,
I am made with an egg,
I have plenty of backbone, but lack a good leg,
I peel layers like onions, but still remain whole,
I can be long, like a flagpole, yet fit in a hole.

Asked by Neha on 07 Dec 2023

On a beautiful Sunday morning, You ordered a hot tea to your hotel room and suddenly you remember an important thing that needed to be done right now will take around 3 minutes to complete.
Like most people you like your tea to be hot while drinking so, when should you pour cream in the tea?
1. straight away
2. Just people, you drink the team
3. Its does not matter

Asked by Neha on 24 Jun 2023

What can you hold in your right hand, but never in your left hand?

Asked by Neha on 13 Jul 2025


There are 4 big houses. They are made from the materials: red marble, green marble, white marble and blue marble.

* Mrs Jennifer's house is somewhere to the left of the green marble one and the third one alone is white marble.
* Mrs Sharon owns a red marbles house and Mr Cruz does not live at either end, but lives somewhere to the right of the blue marbles house.
* Mr Danny lives in the fourth house, while the first house is not made from red marble.

Who lives where, and what is their house made from?

Asked by Neha on 15 May 2026

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

Find the age

Asked by Neha on 10 Apr 2021

If 21x = 79x, what is the value of x?

Asked by Neha on 19 Oct 2023


You can take four of the five letters out of this word, but the pronunciation never changes. What is the word?

Asked by Neha on 05 Aug 2024

Hot Articles

Amazing Facts

Jigsaw puzzles

Jigsaw puzzles soared in popularity during the great depression, as they provided a cheap, long-lasting, recyclable form of entertainment.