What is common among 11, 69, and 88?

What does the below rebus puzzle mean?

With the help clues provided in the image, can you find the 5 digit key?

Find the mistake in the below maths equations

A = 2
A(A-1) = 2(A-1)
A2-A = 2A-2
A2-2A = A-2
A(A-2) = A-2
A = 1

Which number should replace the question mark?

What runs around the whole yard without moving?

There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

Two guards were on duty outside a barracks. One faced up the road to watch for anyone approaching from the North. The other looked down the road to see if anyone approached from the South. Suddenly one of them said to the other, "Why are you smiling?"

How did he know his companion was smiling?

You have to fill the below given grid in a manner that every row and column contains the digits 1 to 6. Also, make sure that the squares that are connected with each other must contains the same digit.

What is so fragile that saying its name breaks it?