The more of this there is, the less you see. What is it?

Place the numbers from 1 to 9 in the circles in a manner that each side of the triangle sums up to 17.

Krish is 45 years old and his mother Crishtina is 73 years old.

Can you find out how many years ago, his mother was three times his age?

A seven-year-old kid challenged his classmates that he can make the number one disappear by adding something to it.

How can he do that?

A man has eighty-one cows ( numbered 1,2,3...81 as such). The beauty is that cow no. 1 gives 1ltr of milk, cow no. 2 gives 2ltrs of milk and so on. The man wants to equally distribute the cows among his nine sons so that each one of them gets the same quantity of milk.

Can you find out the missing number?

? 4 5 3 5

9 5 7 10 3

Count the number of triangles in the picture below:

Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

Jenifer and Jesica are having a conversation.

Jenifer: I am definitely not over 30.
Jesica: I am 28 and you are surely 5 years older to me at least.
Jenifer: No, you are at least 29.

You are told that both of them are lying throughout in the conversation. Can you find their respective ages?

I have one of the three numbers: 1, 2, or 3 in my mind. I speak only truth. You can ask me just one question for which I will only reply in yes or no or don't know. What question will you ask from me so that you are able to know the number?