You are given four results as below:
1111 = F
2222 = E
3333 = T
Then, can you find out how to code 4444?

Analyze and find the missing item in the sequence:
16, 06, 68, 88, __, 98

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?

I never was there, I am always to be.
You have never ever seen me, not ever you will.
Yet I am the confidence of everyone.

Who Am I?

Can you solve below mathematical equation?

2^1234 - 2^1233

What occurs twice in a week, once in a year but never in a day?

Find the next number in the following series:
6, 14, 26, 98, __?

Can you find out the remainder when 3^300 is divided by 5?

Count the number of triangles in the given picture.

I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?