Archive for May, 2013

Playing with numbers

Here is a math trick that you could use to impress a friend, a classmate, a parent, a brother or a sister who knows how to add, subtract and multiply.

Ask the person to think of a number but not tell you what it is. Then ask that person to do the following:

Bǎ nà shùzì jiāshàng wǔ.
Add 5 to the number.

Bǎ jiéguǒ chéng yǐ èr shí.
Multiply the result by 20.

Qù diào zuì yòubiān de líng.
Erase the zero on the right side.

Cóng jiéguǒ jiǎn qù shí.
Subtract 10 from the result.

Bǎ nà zuìhòu de jiéguǒ gàosù nǐ.
Tell you the final result.

You will say, “Aha! I know what number you had in mind.”
And you will tell that person the correct number.

(Between you and me, the correct number is one half of the final result of the above calculations. Do you know why this works?)

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