Throughout the ages men have been interested in mystery and in things that are strange, interesting and starling. As in the past, modern magic derives much of its charm from the phenomena which superficially are perplexing. With the maturity of mathematics, a term so called ‘**Mathematical Magic**‘ had come into its own in 20th century. There were mathematical geniuses behind this term who had those extraordinary qualities which were not possessed by others.

As I am making a series of posts on ‘mathematical tricks’ In this post I want to share a simple **math trick** with you. By using this astonishing math trick, one can easily guess whether other person is **lying** or **not**.. You can use this trick in any way you like. You just need to follow the steps of this trick and then you can apply it to any preferred scenario which best suits you.

This trick is so simple, interesting and easy to execute on anyone. You can be an expert lie detector in few minutes. As I already said we can apply it in various scenarios but I have chosen a specific scenario here. In this post we will try to find whether someone is telling his age right or wrong. If he or she is lying about his/her age, we can easily detect a lie. Normally girls lie about their age. They usually snip some years from their age. You can perform this trick on girls and evaluate them. But you need not to tell them that you can detect a lie.

#### Demonstration

Let’s discuss the steps in a table. First column shows what you have to ask your victim. Second column shows what will happen when someone speaks truth. Third column shows what will happen when someone is lying.

What you tell a victim to do | The truth | A Lie |

1. Write down your age upto the end of this year on a paper. Don’t tell it to me. | Ali is 25 and he writes 25 | Sara is 23 but she writes 20 |

2. Add to this your next year’s age. | Ali adds 25 + 26 = 51 | Sara adds 20 + 21 = 41 |

3. Multiply by 5. | Ali gets 51 x 5 = 255 | Sara gets 41 x 5 = 205 |

4. Now ask other person to add the last digit of the year in which you were born. | Ali notices, he was born in 1993 so he adds 255 + 3 = 258. | Sara will not lie here considering that the last digit of her birth year cannot reveal her lie. She adds 205 + 5 = 210 |

**Take Ali first**: Now subtract 5 from his answer. 258 – 5 = 253 and note the first two digits (25) are the same which Ali wrote down as his age. Now subtract the remaining digit (3) from the current year i.e. 2018. You will get 2018 – 3 = 2015. Now chop off the other digits from this except the last digit. i.e. ~~201~~5 becomes 5. And now check that this 5 and the 5 of 25 are **same**. It means Ali is **not lying** about his age.

**Now take Sara:** Now subtract 5 from her answer. 210 – 5 = 205 and note the first two digits (20) are the same which Sara wrote down as her age. Now subtract the remaining digit (5) from the current year i.e. 2018. You will get 2018 – 5 = 2013. Now chop off the other digits from this except the last digit. i.e. ~~201~~3 becomes 3. And now check that this 3 and the 0 of 20 are **not same**. It means Sara is **lying**. This 3 must be the last digit of Sara’s age. So the true age of Sara is 23 instead of 20.

#### Conclusion

That’s how you can detect whether someone is** lying or not**. You can summarize all the steps needed to perform this trick from first column and then you know how to evaluate the result. The most amazing thing in this trick is that not only you can **detect a lie** but you can **find the truth** as well. Feel free to test it on anyone. Have fun!!

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