What is black when you buy it, red when you use it, and gray when you throw it away?

It is raining today at 11:59 am. What is the probability of sunny weather after 72 hours?

A number with an interesting property:

When I divide it by 2, the remainder is 1.
When I divide it by 3, the remainder is 2.
When I divide it by 4, the remainder is 3.
When I divide it by 5, the remainder is 4.
When I divide it by 6, the remainder is 5.
When I divide it by 7, the remainder is 6.
When I divide it by 8, the remainder is 7.
When I divide it by 9, the remainder is 8.
When I divide it by 10, the remainder is 9.

It's not a small number, but it's not really big, either.
When I looked for a smaller number with this property I couldn't find one.

Can you find it?

Here is a mathematical challenge that will not only engage your brain but also measure your quick-thinking abilities. If you can successfully identify the missing number in such a short span, you are demonstrating exceptional intellectual qualities.

You need to remove four matchsticks from the picture below and still need to maintain the following as in the original image.
1. 1st row contains 12 matchsticks
2. 2nd row contains 12 matchsticks
3. 1st column contains 12 matchsticks
4. 2nd column contains 12 matchsticks

It is always ahead of me yet I can never see it. What is it?

What does an Island and the letter T have in common?

Solve the equation in the image by looking at the pattern closely.

In the formation, you can see a few arranged matchsticks. Can you form three squares by moving just three matchsticks?

Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?