Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

Can you write down eight eights so that they add up to one thousand?

If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?

Christina, Allison and Lena are 3 daughters of John a well-known Mathematician, When I asked John the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters?

The sum of a mother, her baby and her dog's weight is 170 Kg. How much does the baby weigh if the mother weighs 100 kg more than the combined weight of the baby and the dog, and the dog weighs 60 per cent less than the baby?

Find the value of "?" in the ball picture Riddle below:

If in a car race, the man who came two places in front of the last man finished one ahead of the man who came fifth, how many contestants were there?

You need to arrange three 7 and mathematical symbols to form number 1?

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

Can you find out which number multiplied by itself will give the output as 12345678987654321?