# Math Riddles

##### Math Riddle #198 (medium)

Question: John has been hired to paint the numbers 1 through 100 on 100 apartments.

How many times with he have to paint 8?

##### Math Riddle #370 (medium)

Question: There are several books on a bookshelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

##### What is the next number in the sequence 1 11 21... (hard)

Question: What is the next number in the sequence? 1 11 21 1211 111221 312211

##### Where's Waldo riddle (medium)

Question: You create your own Where's Waldo game on a piece of paper. You want your friend to find Waldo but they think you might be pulling a prank on them by not putting Waldo on the paper at all.

How can you prove to your friend that Waldo is on the paper without ruining it for them?

##### Math Riddle #559 (hard)

Question: Sum Sam and Product Pete are in class when their teacher gives Sam the Sum of two numbers and Pete the product of the same two numbers (these numbers are greater than or equal to 2). They must figure out the two numbers.

Sam: I don't know what the numbers are Pete.
Pete: I knew you didn't know the numbers... But neither do I.
Sam: In that case, I do know the numbers.

What are the numbers?