What is a googol?: The number 1 followed by 100 zeros
What is pi?: About 3.14159, the ratio of a circle's circumference to its diameter
When is Pi Day?: March 14 (3/14)
What is the only even prime number?: 2
What is a prime number?: A number greater than 1 with only two factors: 1 and itself
What are the first five prime numbers?: 2, 3, 5, 7, 11
What is a perfect number?: A number equal to the sum of its smaller factors, like 6 (1+2+3)
What is the next perfect number after 6?: 28
What is a square number?: The result of a number times itself, like 25
What are the first five square numbers?: 1, 4, 9, 16, 25
What is a cube number?: A number times itself twice, like 27
What is the Fibonacci sequence?: 1, 1, 2, 3, 5, 8, 13... each number is the sum of the previous two
Where do Fibonacci numbers show up in nature?: In spirals of sunflowers, pinecones and shells
What is the golden ratio?: About 1.618, a special ratio found in art and nature
Who is the father of geometry?: Euclid
What is the Pythagorean theorem?: In a right triangle, a squared plus b squared equals c squared
How many degrees in a circle?: 360
How many degrees in a triangle's angles?: 180
How many degrees in a right angle?: 90
How many sides does a hexagon have?: Six
How many sides does an octagon have?: Eight
What shape is a honeycomb cell?: A hexagon
What is a polygon?: A closed shape with straight sides
What is a number with no end after the decimal and no pattern?: An irrational number, like pi
What is zero?: The number that means none, invented in India
Who invented our digits 0 to 9?: They came from India and spread through the Arab world (Hindu-Arabic numerals)
What number system do computers use?: Binary, using 0 and 1
What is 1,000,000 called?: A million
What is 1,000,000,000 called?: A billion
What is 1,000,000,000,000 called?: A trillion
What is a dozen?: Twelve
What is a gross?: 144, or twelve dozen
What is a score?: Twenty
How many seconds in a minute?: 60
How many minutes in an hour?: 60
How many hours in a day?: 24
How many days in a year?: 365 (366 in a leap year)
How many weeks in a year?: 52
What are Roman numerals for 1, 5, 10, 50, 100?: I, V, X, L, C
What is the Roman numeral for 500?: D
What is the Roman numeral for 1,000?: M
What is 12 x 12?: 144
What is 9 x 9?: 81
What is 7 x 8?: 56
What happens when you add the digits of a multiple of 9?: The digits add up to a multiple of 9
What is the 9s trick on fingers?: Fold down the finger for the number; fingers left of it are tens and right are ones
What is a tessellation?: A pattern of shapes that fit together with no gaps
What shape tiles a floor without gaps?: Squares, triangles and hexagons
What is symmetry?: When one half of a shape mirrors the other
How many lines of symmetry does a square have?: Four
How many lines of symmetry does a circle have?: Endless
What is an average?: The sum of numbers divided by how many there are
What is a mean, median and mode?: Average, middle value, and most common value
What does 'infinity' mean?: Without end
What is the symbol for infinity?: A sideways eight
What is the Möbius strip?: A one-sided loop made by twisting a paper strip and joining its ends
Who was Ada Lovelace?: An early thinker about computer programs in the 1840s
Who was Carl Friedrich Gauss?: A German mathematician; as a boy he quickly added 1 to 100
What is the sum of 1 to 100?: 5,050
What is 1 + 2 + 3 + 4 + 5?: 15
Why is a circle special?: Every point on it is the same distance from the center
How many cents in a dollar?: 100
What is a percent?: Out of 100
What is 50 percent of 80?: 40
What number is half of 100?: 50
What is the biggest 3-digit number?: 999

Free flashcards from Peabody at peabody.kids/flashcards/fun-math-fun-facts