What four weights can be used to balance from 1 to 30 pounds?

If eleven plus two equals one, what does nine plus five equal?

As you can see that fifteen matches have been used to form an arrangement. What you have to do is remove any six of them to make them ten.

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

Look at the picture and find out which square is not linked with any of the other squares.

How do you go from 98 to 720 using just one letter?

Can you count the number of triangles in the given picture?

What is the next number in this series?

4,12,84,3612....

Can you solve the below tricky visual equation?

Twenty frogs are sitting on a log floating on the surface of a river. Two of them decide to jump off into the water.

How many frogs are there on the log at this moment?