A 3-digit result of any number multiplied by

**11**has its middle digit the sum of other two, like: 21 × 11 =**2***3***1**(**2**+**1**=*3*) 13 × 11 =**1***4***3**(**1**+**3**=*4*) 44 × 11 =**4***8***4**(**4**+**4**=*8*) ... etc. Submitted by: Catrine Montano - Surigao, PhilippinesThe value of

**zero**was first used by the ancient Indian mathematician**Aryabhata**. Submitted by: Sundara Moorthy - Tiruppur, Tamil Nadu, IndiaThe sum of the digits of a number which is a multiple of

**9**is always 9, ie,**45 :***4+5*= 9**1980 :**1+9+8+0=18 :*1+8*= 9**214164 :**2+1+4+1+6+4=18 :*1+8*= 9 etc. Submitted by: Vighneswar - India
9 × 9 + 7 = 88
98 × 9 + 6 = 888
987 × 9 + 5 = 8888
9876 × 9 + 4 = 88888
98765 × 9 + 3 = 888888
...

*(Multiplication & Succession.)*Submitted by: Tyler - United StatesThe

**implicit curve**equation (x^{2}+y^{2}-1)^{3}-x^{2}y^{3}=0 produces the heart shape. Submitted by: Hyde - Toronto, Ontario, CanadaThe term

**Googol**(10^{100}, ie, 10 followed by 100 zeros) was invented by a 9-year old boy**Milton Sirotta**. Submitted by: Cynthia - San Francisco, California, United StatesThe

**Reuleaux Triangle**is a shape of*constant width*other than a circle. Submitted by: Adarsh - Guraon, India
17 689 = 133

^{2}177 6889 = 1333^{2}1777 68889 = 13333^{2}17777 688889 = 133333^{2}... Submitted by: Laxmana Perumal - Nagercoil, IndiaThe Seven Unsolved

**Millennium Prize**Math Problems are:**1**. P versus NP problem**2**. Hodge Conjecture**3**. Poincaré conjecture (solved in 2002)**4**. Riemann Hypothesis**5**. Yang-Mills Existence and Mass Gap**6**. Navier-Stokes Existence and Smoothness**7**. Birch and Swinnerton-Dyer Conjecture Submitted by: Ravi - Mississauga, Ontario, Canada The

**Fibonacci sequence**are numbers where each following number is the sum of the previous two: 0 1 1 2 3 5 8 13 21 34 55 89 ... Submitted by: Matt - California, United StatesA

**Palindrome Number**is a number that reads the same backwards and forward, e.g. 13431. Submitted by: Yusuf - Victoria, AustraliaA US dollar can be made into small change in

**293**ways.You can remember the value of

**Pi**(3.1415926) by counting each word's letters in "**May I have a large container of coffee?**"
1 × 8 + 1 = 9
12 × 8 + 2 = 98
123 × 8 + 3 = 987
1234 × 8 + 4 = 9876
12345 × 8 + 5 = 98765
123456 × 8 + 6 = 987654
...

*(Multiplication & Succession.)*Submitted by: Moi, Canada.**142857**is a cyclic number, i.e., its digits are rotated around when multiplied by any number from 1 to 6. Like this: 142857 × 1 = 142857 142857 × 5 = 7 14285 142857 × 4 = 57 1428 142857 × 6 = 857 142 142857 × 2 = 2857 14 142857 × 3 = 42857 1 Submitted by: Moi, Canada.

**1089**multiplied by

**9**gives an exact reverse: 9801.

From 0 to 1000, the letter "

**A**" only appears in 1000 ("one thousand"). Submitted by: Ramil Argete**2**is called the "oddest"

**Even-Prime**number. 2 is a unique Even-Prime because while all Evens are divisible by 2, any number apart from 2 that is divisible by 2, is not a Prime.

1 × 9 + 2 = 11
12 × 9 + 3 = 111
123 × 9 + 4 = 1111
1234 × 9 + 5 = 11111
12345 × 9 + 6 = 111111
...

*(Multiplication & Succession.)*40 when written "

**forty**" is the only number with letters in alphabetical order, while "one" is the only one with letters in reverse order.