How many triangles are there on the puzzle below?

When can we add 2 to 11 and get 1 as the correct answer?

Below is the sum of symbols in each row and column in the figure. Analyzing the figure, can you find out the value of the symbols?

What is the next number?

77, 49, 36, 18 ?

Solve the rebus riddle in the picture below.

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

If 21x = 79x, what is the value of x?

John is 45 years older than his son Jacob. If you find similarities between their ages, both of their ages contain prime numbers as the digits. Also, John's age is the reverse of Jacob's age.

Can you find their ages?

What does the following represent?

N N N N N N N

A A A A A A A

C C C C C C C

Find the next number in the sequence

1, 2, 6, 21, 88, __?