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

Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

What does below chemistry rebus means?

A cricket has 6 legs, a squirrel has 4 legs and a spider has 8 legs.

In a local zoo, it was found that the total number of legs is 612. Also, there are equal number of each of the above animals/insects.

Can you find out how many animals are there in the zoo?

Can you count the number of quadrilaterals in the picture below?

Which is faster, Heat or Cold ? Explain.

I am soft and cuddly that soothe your heart. But, If you pick my last name I am going to tear you all apart. Who am I?

John is the son of Jacob.
So,
Jacob is the_____of John's father?

John leaves home and then he takes three right turns. John wants to return to home but he was scared of Jacob, who is wearing a mask.

What is John Situation ?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?