Amazing Facts

1. The '/' mark that is put through a number when regrouping during subtraction is called a 'crutch'. 
2. It is believed that almost 6000 years age, Chinese were the first to use addition in an extensive way but addition is formalized as a mathematical operation only much later. The symbol for addition, +, was invented by Micheal Stiple in 1544. The symbol owes its origin to the word "et" in Latin.
3. One million seconds is equal to approximately 11 and a half days.
4. Nicolas d'Oresme was the first person who used the plus sign (+) to write 'and' in short from. Many years later, Micheal Stiple introduced this plus sign (+) for the addition of numbers.
5. The tongue of a blue whale is heavier than that of an adult elephant! 
6. Before clock were invented, sundials were used to tell time. You can tell the time on a sundial by looking at the position of its shadow.
7. 2 is actually the only even prime number.
8. Atlantic salmon can leap as high as 4.5 m out of the water.
9. Regular Hexagons can be seen in nature on the end faces of volcanic rocks at the Giant's Causeway in Northern Ireland. 
10. On the shortest day of the year, also known as the winter solstice. Alaska has only around 5 h 27 min of sunlight. The sun rises at around 10:14 am and sets at around 3:41 pm.
11. Before money was introduced, people exchanged goods using the 'barter system'. If a farmer needed a piece of cloth, he would exchange his surplus grains in exchange for cloth from a merchant, who in turn needs the grains to feed his family.
12. Though each snowflake is a symmetrical figure, no two snowflakes in the world are the same. Each has its own unique shape and symmetry.
13. Number 9 is a magic number, because if you multiply a number with 9 and add all the digits, the sum would always be 9.
14. 9 is the smallest odd composite number.
15. 'FOUR' is the only number in the English language that is spelt with the same number of letters as the number itself.
16. Ancient Egyptians used symbols to stand for numbers. For example, they used | to stand for 1 and ⋂ to stand for 10. 
17. The word fraction comes from the Latin word 'fractus' which means to 'break'.
18. A giraffe can clean its ears with its 53 cm long tongue.
19. Stretch out your arms horizontally. The length of your arm span is almost the same as your height!
20. One million seconds is equal to approximately 11 and a half days.
21.  The mark that is put through a number when regrouping during subtraction is called a 'crutch'.
22. The 'x' symbol for multiplication was only introduced in 1631 by William Oughtred an English Mathematician. Before that a dot "." is used to represent the multiplication.  
23. An orca whale can hold its breath for up to one-fourth of an hour. That is about 15 minutes. 
24. 'Decimal Day' is celebrated on 15 February, 1971. It was the day when the United Kingdom and Ireland decimalised their currency.
25. The percent symbol was used in the 15th century as a way to express parts of a 'cento', or one hundred.
26. The ratio of the size of the Sun to the size of the Earth is about 108 : 1
27. The price tag was invented in the 1860s. John Wanamker, a storekeeper in Philadelphia, is registered as the inventor of price tag.
28. Skew lines lie on different planes. Skew lines are two lines that do not intersect and are not parallel too.
29. 'Trapezium' is also the name of a bone found in our hands. 
30. Some psychologists use the inkblot test (also called the "Rorschach" test) to examine the personality characteristics and emotional functioning of patients. 
31. The world largest postage stamp ever issued measured 60 cm by 49.3 cm.
32. The numerical digits we use today such as 1, 2 and 3 are based on the Arabic number system developed over 1000 years ago.
33. Roman numerals do not have a '0' (zero). This system also does not use place value to write numbers.
34. Mathematicians first used the addition sign (+) in the 16th century. 
35. It is believed that Ancient Egyptians started using subtraction as far back as 3000 B.C.
36. Multiples of 9 always have digits that add up to 9.
37. Did you know that the division symbol is called obelus? Its plural form is obeluses or obeli. It is an Ancient Greek word which means a pointed pillar. It was invented by Aristarchus but was first used as a symbol for division in 1659 by Johann Rahn in his book on Algebra.
38. The Millau Viaduct is a bridge in France. It is the tallest bridge in the world. It has a height of 343 m. It is taller than the Eiffel Tower which is 300 m tall. 
39. Mount Everest is the tallest mountain in the world. It has a height of 8848 m. 
40. In the past, people could use coins of value of 5 paise, 10 paise, 25 paise, and 50 paise. These coins are no longer in circulation. Some people collect these coins as a hobby.
41. In some Asian countries like China and Japan, five tally marks look like this: 正. It is a Chinese character which means 'proper'. 
42. As early as 1000 A.D., the Maya Civilisation has used a dot to represent one, and a bar to represent five and a shell symbol represented zero. The Maya could write any number from 0 to 19 using a combination of these symbols.
    
    
43. Nicolas d' Oresme was the first person who used the plus sign (+) to write 'and' in short form. Many years later, Michael Stiple introduced this plus sign (+) for the addition of numbers.
44. All wheels are in the shape of a circle. They are used in cars, trains and also in some machines. What could we move without a wheel? But did you know? At the time of its invention, it was not used for transportation, but as a potter's wheel. This was many years before wheels were used in chariots.
45. The tongue of a blue whale is heavier than that of an adult elephant!
46. Before clocks were invented, sundials were used to tell time. You can tell the time on a sundial by looking at the position of its shadow.
47. When coins first appeared, their values were determined by how heavy they were.
48. When a number is multiplied by 10, and 10 is added to the result, and then the sum is divided by 10, the result will always be the successor of the original number.
49. Two houses will be adjacent to each other if they have a common wall. 
50. Prime numbers that differ by 2, such as 5 and 7, are called twin primes.
51. 'Divisible by' and 'can be exactly divisible by' means the same.