**1.** Zero ( 0 ) is the only number which can not be represented by Roman numerals.

**2. **What comes after a million, billion and trillion? A quadrillion, quintillion, sextillion, septillion, octillion, nonillion, decillion and undecillion.

**3.** Plus (+) and Minus (-) sign symbols were used as early as 1489 A.D

**4**. 2 and 5 are the only primes that end in 2 or 5

**5**. An icosagon is a shape with 20 sides

**6. **Among all shapes with the same perimeter a circle has the largest area.

**7.** Among all shapes with the same area circle has the shortest perimeter

**8.** 40 when written “forty” is the only number with letters in alphabetical order, while “one” is the only one with letters in reverse order

**9.** ‘FOUR’ is the only number in the English language that is spelt with the same number of letters as the number itself

**10.** From 0 to 1,000, the letter “A” only appears in 1,000 (“one thousand”)

**11.** 12,345,678,987,654,321 is the product of 111,111,111 x 111,111,111. Notice the sequence of the numbers 1 to 9 and back to 1.

**12.** Have you ever noticed that the opposite sides a die always add up to seven (7)

**13.** Trigonometry is the study of the relationship between the angles of triangles and their sides

**14.** Abacus is considered the origin of the calculator

**15.** Here is an interesting trick to check divisibility of any number by number 3.A number is divisible by three if the sum of its digits is divisible by three (3)

**16.** Do you know the magic of no. nine (9)? Multiply any number with nine (9 ) and then sum all individual digits of the result (product) to make it single digit, the sum of all these individual digits would always be nine (9).

**17.** If you add up the numbers 1-100 consecutively (1+2+3+4+5…) the total is 5050

**18.** A ‘jiffy’ is an actual unit of time for 1/100th of a second

**19.** Have you heard about a Palindrome Number? It is a number that reads the same backwards and forward, e.g. 12421

**20.** Have you heard about Fibonacci? It is the sequence of numbers wherein a number is the result of adding the two numbers before it! Here is an example: 1, 1, 2, 3, 5, 8, 13, 21, 34, and so on