Riddle: One is to three as three is to five and five is to four and four is the magic number. What is the pattern?
Answer: One has three letters in the word three has five letters in it five has four letters and four has four letters in it (if you try more numbers they will always come back to the number four: so four is the magic number)
Riddle: If a boy blows 18 bubbles, Then pops 6 eats 7 and then He pops 5 and blows 1. How many are left?
Answer: 1.
Riddle: The ages of a father and son add up to 66. The father's age is the son's age reversed. How old could they be? (3 possible solutions).
Answer: 51 and 15. 42 and 24. 60 and 06.
Riddle: What did the triangle say to the circle?
Answer: You’re pointless.
Riddle: What two whole, positive numbers that have a one-digit answer when multiplied and a two-digit answer when added?
Answer: 1 and 9.
Riddle: You want to boil a two-minute egg. If you only have a three-minute timer (hourglass), a four-minute timer and a five-minute timer, how can you boil the egg for only two minutes?
Answer: Once the water is boiling, turn the three-minute timer and five-minute timer over. When the three-minute timer runs out, put the egg in the boiling water. When the five-minute timer runs out, two minutes have elapsed and it is time take the egg out of the water. You don't need the four-minute timer for this riddle.
Riddle: 81 x 9 = 801. What must you do to make the this equation true?
Answer: Turn it upside down.  108 = 6 x 18.
Riddle: How much will a 38° angle measure when looked at under a microscope that magnifies ten times?
Answer: It will still be 38°.
Riddle: How can you make the following equation true by drawing only one straight line: 5+5+5=550? Can you figure it out?
Answer: Draw a line on the first plus sign that turns it into a 4! The equation then becomes true: 545+5=550. You could also change the equal symbol to a crossed out equal symbol which means "not equal to".
Riddle: What did the little lobster get on its math test?
Answer: Sea-plus.