By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

See the given image carefully. What you have to do is move the blue checkers in the position of the black checkers and vice versa. You are only allowed to move the checker to an adjacent empty space. Do it in the least possible moves.

How many triangles are there in the picture below?

You board a train. The train will have to enter a tunnel soon. You are claustrophobic. Which place is the best for you to sit?

A wooden log balances equally on the scales when weighed with three-quarters of a pound and three-quarters of a wooden log.

Can you calculate the weight of the entire wooden log?

Take 9 from 6, 10 from 9, 50 from 40, and leave 6.

How Come ??

Can you find out what is missing?

1 3 5
2 4 ?

Hint: It's not six. Think out of the box.

A man has a barrel filled with oil that weighs 100 pounds, and then he puts something into it. Now the barrel weighs less than 100 pounds. What did he put in the barrel?

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?

I am thinking of a five-digit number such that:
The first and last digits are the same, their submission is an even number and multiplication is an odd number and is equal to the fourth number. Subtract five from it and we obtain the second number. Then divide into exact halves and we get the 3rd number.

What number I am thinking of?