Can you solve this tricky maths equation problem by replacing it? mark with the correct symbol?

19834 -----: 187
15921 -----: 153
17561 -----: 139
13734 -----: ???

Can you start the fire using two pieces of wood?

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?

Count the squares in the matchstick puzzle below?

It is deaf, Dumb and Blind!!!

Still, always tells the truth. What is it?

What 5-letter word typed in all capital letters can be read the same upside down?

What does does this rebus picture means ?

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

In the city of Brain Teasers, 5% of people do not list their phone numbers. Now if we select random 100 people from the phone directory, then how many people selected will have unlisted phone numbers?

Thirty friends were on a hiking trip when they decided to enjoy the bonfire. They assembled for it and agreed to play a game. For that, they divided themselves into five teams with seven members each, forming five rows.

How did they manage to achieve this formation?