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

What number divided by 4 is the same as that number minus 4?

What has many teeth, but cannot bite?

Replace the alphabet with the number such that the below equation holds.

HAPPY
+ DIWALI
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HDLALA
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A girl is twice as old as her brother and half as old as her father. In 50 years, her brother will be half as old as his father. How old is the daughter now?

Can you write down eight eights so that they add up to one thousand?

A man was going to bleach his socks because they had gotten muddy the day before. As he was pouring the bleach into the washing machine, he spilt some on the floor. He got some cleaning fluid and mopped it up with a rag. Minutes later he was dead. What killed him?

What does man love more than life, hate more than death or mortal strife; That which contented men desire; the poor have, the rich require; the miser spends, the spendthrift saves, and all men carry to their graves?

What is the difference between a jeweller and a jailer?

Which English verb becomes past tense just by rearranging the letters?