all about numbers......

ALL ABOUT NUMBERS

7 Answers

21
omkar ·

TYPE 1: Multiplying by 12

Consider

Example 1 :12 X 7

Step 1: Multiply the 1 of the 12 by the
number we are multiplying by, in this case 7. So 1 X 7 = 7.

Step 2: Multiply this 7 by 10 giving 70.

Step 3: Now multiply the 7 by the 2 of twelve giving 14. Add this to 70 giving 84.

Therefore 7 X 12 = 84

Example 2: 17 X 12

Step 1: Multiply the 1 of the 12 by the
number we are multiplying by, in this case 17. So 1 X 7 =1 7.

Step 2: Multiply this 17 by 10 giving 170.

Step 3: Now multiply the 17 by the 2 of twelve giving 34. Add this to 170 giving 204.

Therefore 17 X 12 = 204

21
omkar ·

Instant Subtraction

Use the formula ALL FROM 9 AND THE LAST FROM 10 to perform instant subtractions.

Example 1: 1000 – 357 = 643

Step 1: Take each figure in 357 and subtract it from 9 and the last figure from 10.

1 0 0 0 - 3 5 7 = 6 4 3

( 9 - 3 = 6

9 - 4 = 5

10 - 7 = 3 )

So the answer is 1000 – 357 = 643

Example 2: 10,000 – 1049 = 8951

Step 1: Take each figure in 1049 and subtract it from 9 and the last figure from 10.

1 0 0 0 0 - 1 0 4 9 = 6 4 3

( 9 - 1 = 8

9 - 0 = 9

9 - 4 = 5

10 - 9 = 1 )

So the answer is 1000 – 357 = 643

21
omkar ·

SQUARING NUMBERS ENDING WITH 5

Example 1: 752 = 5625

75 2= 75 X 75

Step1: Multiply the first number 7, by the next preceding number, which is 8.

Thus, we have 7 X 8 = 56, which is the first part of the answer.

Step 2: The last part will be the square of 5, which is 25

Thus the answer for 752 is divided into 2 parts: 56 and 25 which when combined together gives 5625.

21
omkar ·

DIVIDING A NUMBER BY 9

Example 1: 23 / 9

Step 1: The first figure of 23 is 2, thus the quotient is 2.

Step 2: The sum of the 2 digits 2 and 3 is 5, thus the remainder is 5.

Example 2: 43 / 9

Step 1: The first figure of 43 is 4, thus the quotient is 4.

Step 2: The sum of the 2 digits 4 and 3 is 7, thus the remainder is 7.

21
omkar ·

these r sum interisting information abt 'numbers'...jst watch out...

d greatest no. one can make by 3 digit is 99^9 !! it can b shown dat dis no. has abt 369693100 digits.assuming there can b 50 digits per line,nd 40 lines per page,in order to write d no.one will need at least 184 vol.of books each of 1000pages ,forthmore yet another vol. of abt 847 pages!!

Perfect no.: a no. is called perfect if it equals d sum of all its divisor(xcept d no. itself).d 1 st four perfect nos. r 6,28,496,8128.nd they r known to be Euclid..but most interesting is dat it took 17 century after euclidbefore d fifth one was discovered..which happehs 2 b 33550336..till date we know 38 of these nos.nd amazingly dey r all even no. ONE OF D OLDEST UNSOLVED PROBLEM IN MATH IS'DOES THERE NE ODD PERFECT NO.???'

magic of number??-now frndz lets paly.. take a 3 digit no.such dat its ist nd last digits r different.reverse them nd substract the smaller one frm d other reverse d result and add it to d result. interestingly u'll always get 1089.(may not valid for 100,102..).

now check dat-

12-1=,

3*(2+4)=
95/5=9+5+5
3+3+3+1+1=33/3+1-1....if u knw more like dis plz tell me(nudge me).

d following two nos.r equals to thesum of the factorial of their respective digits-

145=1!+4!+5!, 40585=4!+0!+5!+8!+5!......do u know more???

7*9=63

77*99=7623
777*999=776223
7777*9999=77762223....

123456789*9=111111111

*18=222222222
*27=333333333
*36=444444444

21
omkar ·

Beauty of Mathematics
Sequential Inputs of numbers with 8

1 x 8 + 1 = 9
12 x 8 + 2 = 98
123 x 8 + 3 = 987
1234 x 8 + 4 = 9876
12345 x 8 + 5 = 98765
123456 x 8 + 6 = 987654
1234567 x 8 + 7 = 9876543
12345678 x 8 + 8 = 98765432
123456789 x 8 + 9 = 987654321

Sequential 1's with 9

1 x 9 + 2 = 11
12 x 9 + 3 = 111
123 x 9 + 4 = 1111
1234 x 9 + 5 = 11111
12345 x 9 + 6 = 111111
123456 x 9 + 7 = 1111111
1234567 x 9 + 8 = 11111111
12345678 x 9 + 9 = 111111111
123456789 x 9 + 10 = 1111111111

Sequential 8's with 9

9 x 9 + 7 = 88
98 x 9 + 6 = 888
987 x 9 + 5 = 8888
9876 x 9 + 4 = 88888
98765 x 9 + 3 = 888888
987654 x 9 + 2 = 8888888
9876543 x 9 + 1 = 88888888
98765432 x 9 + 0 = 888888888

Numeric Palindrome with 1's

1 x 1 = 1
11 x 11 = 121
111 x 111 = 12321
1111 x 1111 = 1234321
11111 x 11111 = 123454321
111111 x 111111 = 12345654321
1111111 x 1111111 = 1234567654321
11111111 x 11111111 = 123456787654321
111111111 x 111111111 = 12345678987654321

Without 8

12345679 x 9 = 111111111
12345679 x 18 = 222222222
12345679 x 27 = 333333333
12345679 x 36 = 444444444
12345679 x 45 = 555555555
12345679 x 54 = 666666666
12345679 x 63 = 777777777
12345679 x 72 = 888888888
12345679 x 81 = 999999999

Sequential Inputs of 9

9 x 9 = 81
99 x 99 = 9801
999 x 999 = 998001
9999 x 9999 = 99980001
99999 x 99999 = 9999800001
999999 x 999999 = 999998000001
9999999 x 9999999 = 99999980000001
99999999 x 99999999 = 9999999800000001
999999999 x 999999999 = 999999998000000001
......................................

Sequential Inputs of 6

6 x 7 = 42
66 x 67 = 4422
666 x 667 = 444222
6666 x 6667 = 44442222
66666 x 66667 = 4444422222
666666 x 666667 = 444444222222
6666666 x 6666667 = 44444442222222
66666666 x 66666667 = 4444444422222222
666666666 x 666666667 = 444444444222222222
......................................

Amazing Prime Numbers Here are few amazing prime numbers, these prime numbers were proved by the XVIIIth century.

31
331
3331
33331
333331
3333331
33333331

The next number 333333331 is not a prime number. Whereas it is multiplied by 17 x 19607843 = 333333331.

Names for Powers of 10
Values Zero's Names
100 0 One
101 1 Ten
102 2 Hundred
103 3 Thousand
104 4 Myriad
106 6 Million
109 9 Billion
1012 12 Trillion
1015 15 Quadrillion
1018 18 Quintillion
1021 21 Sextillion
1024 24 Septillion
1027 27 Octillion
1030 30 Nonillion
1033 33 Decillion
1036 36 Undecillion
1039 39 Duodecillion
1042 42 Tredecillion
1045 45 Quattuordecillion
1048 48 Quindecillion
1051 51 Sexdecillion
1054 54 Septdecillion / Septendecillion
1057 57 Octodecillion
1060 60 Nondecillion / Novemdecillion
1063 63 Vigintillion
1066 66 Unvigintillion
1069 69 Duovigintillion
1072 72 Trevigintillion
1075 75 Quattuorvigintillion
1078 78 Quinvigintillion
1081 81 Sexvigintillion
1084 84 Septenvigintillion
1087 87 Octovigintillion
1090 90 Novemvigintillionn
1093 93 Trigintillion
1096 96 Untrigintillion
1099 99 Duotrigintillion
10102 102 Trestrigintillion
10120 120 Novemtrigintillion
10123 123 Quadragintillion
10138 138 Quinto-Quadragintillion
10153 153 Quinquagintillion
10180 180 Novemquinquagintillion
10183 183 Sexagintillion
10213 213 Septuagintillion
10240 240 Novemseptuagintillion
10243 243 Octogintillion
10261 261 Sexoctogintillion
10273 273 Nonagintillion
10300 300 Novemnonagintillion
10303 303 Centillion
10309 309 Duocentillion
10312 312 Trescentillion
10351 351 Centumsedecillion
10366 366 Primo-Vigesimo-Centillion
10402 402 Trestrigintacentillion
10603 603 Ducentillion
10624 624 Septenducentillion
10903 903 Trecentillion
102421 2421 Sexoctingentillion
103003 3003 Millillion
103000003 3000003 Milli-Millillion

Trick Play

Trick 1: Number below 10
Step1: Think of a number below 10.
Step2: Double the number you have thought.
Step3: Add 6 with the getting result.
Step4: Half the answer, that is divide it by 2.
Step5: Take away the number you have thought from the answer, that is, subtract the answer from the number you have thought.
Answer: 3

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Trick 2: Any Number
Step1: Think of any number.
Step2: Subtract the number you have thought with 1.
Step3: Multiply the result with 3.
Step4: Add 12 with the result.
Step5: Divide the answer by 3.
Step6: Add 5 with the answer.
Step7: Take away the number you have thought from the answer, that is, subtract the answer from the number you have thought.
Answer: 8

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Trick 3: Any Number
Step1: Think of any number.
Step2: Multiply the number you have thought with 3.
Step3: Add 45 with the result.
Step4: Double the result.
Step5: Divide the answer by 6.
Step6: Take away the number you have thought from the answer, that is, subtract the answer from the number you have thought.
Answer: 15

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Trick 4: Same 3 Digit Number
Step1: Think of any 3 digit number, but each of the digits must be the same as. Ex: 333, 666.
Step2: Add up the digits.
Step3: Divide the 3 digit number with the digits added up.

Answer: 37

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Trick 5: 2 Single Digit Numbers
Step1: Think of 2 single digit numbers.
Step2: Take any one of the number among them and double it.
Step3: Add 5 with the result.
Step4: Multiply the result with 5.
Step5: Add the second number to the answer.
Step6: Subtract the answer with 4.
Step7: Subtract the answer again with 21.

Answer: 2 Single Digit Numbers.

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Trick 6: 1, 2, 4, 5, 7, 8
Step1: Choose a number from 1 to 6.
Step2: Multiply the number with 9.
Step3: Multiply the result with 111.
Step4: Multiply the result by 1001.
Step5: Divide the answer by 7.

Answer: All the above numbers will be present.

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Trick 7: 1089
Step1: Think of a 3 digit number.
Step2: Arrange the number in descending order.
Step3: Reverse the number and subtract it with the result.
Step4: Remember it and reverse the answer mentally.
Step5: Add it with the result, you have got.

Answer: 1089

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Trick 8: x7x11x13
Step1: Think of a 3 digit number.
Step2: Multiply it with x7x11x13.

Ex: Number: 456, Answer: 456456

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Trick 9: x3x7x13x37
Step1: Think of a 2 digit number.
Step2: Multiply it with x3x7x13x37.

Ex: Number: 45, Answer: 454545

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Trick 10: 9091
Step1: Think of a 5 digit number.
Step2: Multiply it with 11.
Step3: Multiply it with 9091.

Ex: Number: 12345, Answer: 1234512345

Day of the Date
Day of the Week:
January has 31 days. It means that every date in February will be 3 days later than the same date in January(28 is 4 weeks exactly). The below table is calculated in such a way. Remember this table which will help you to calculate. January 0
February 3
March 3
April 6
May 1
June 4
July 6
August 2
September 5
October 0
November 3
December 5

Step1: Ask for the Date. Ex: 23rd June 1986
Step2: Number of the month on the list, June is 4.
Step3: Take the date of the month, that is 23
Step4: Take the last 2 digits of the year, that is 86.
Step5: Find out the number of leap years. Divide the last 2 digits of the year by 4, 86 divide by 4 is 21.
Step6: Now add all the 4 numbers: 4 + 23 + 86 + 21 = 134.
Step7: Divide 134 by 7 = 19 remainder 1.
The reminder tells you the day. Sunday 0
Monday 1
Tuesday 2
Wednesday 3
Thursday 4
Friday 5
Saturday 6

Answer: Monday
hope you liked it....

21
omkar ·

Trick 1 : Multiply any two numbers from 11 to 20 in your head.
Take 15 x 13 for example... Place the larger no. first in your mind and then do something like this Take the larger no on the top and the second digit of the smaller no. in the bottom.
15
3
The rest is quite simple. Add 15+3 = 18 . Then multiply 18 x 10 = 180 ...
Now multiply the second digit of both the no.s (ie; 5 x 3 = 15) Now add 180 + 15. Here is the answer 180 + 15 = 195 . Think over it. This is a simple trick. It will help you a lot.

Trick 2 : Multiply any two digit number with 11.
This trick is much simpler than the previous one and it is more useful too. Let the number be 27 . Therefore 27 x 11
Divide the number as 2 _ 7
Add 2+ 7 = 9
Thus the answer is 2 9 7
Wasn't this one simple. But there is one complication. If you take a number like 57 Thus _57 x 11
Divide the number as 5 _ 7
Add 5 + 7 = 12
Now add 1 to 5 and place 2 in the middle so the answer is 5+1_2 _7 = _627
Thus the answer is 627.

Trick 3 : Multiply any number from 1 to 10 by 9 To multiply by 9, try this:

(1) Spread your two hands out and place them on a desk or table in front of you.

(2) To multiply by 3, fold down the 3rd finger from the left. To multiply by 4, it would be the 4th finger and so on.

(3) the answer is 27 ... READ it from the two fingers on the left of the folded down finger and the 7 fingers on the right of it. This one was really cool wasn't it.

Trick 4 : Square a two digit number ending in five. This one is as easy as the previous ones but you have to pay a little more attention to this one . Read carefully :Let the number be 35
35 x 35
Multiply the last digits of both the numbers ; thus ___ 5 x 5 = 25
now add 1 to 3 thus 3 + 1 = 4
multiply 4 x 3 = 12
thus answer 1225

You will have to think over this one carefully.As 5 has to come in the end so the last two digits o the answer will be 25 . Add 1 to the first digit and multiply it by the original first digit . Now this answer forms the digits before the 25. Thus we get an answer.

Trick 5 : Square any two digit number.

Suppose the number is 47 . Look for the nearest multiple of 10 . ie; in this case 50. We will reach 50 if we add 3 to 47. So multiply (47+3) x (47-3) = 50 x 44 = 2200 This is the 1st interim answer.

We had added 3 to reach the nearest multiple of 10 that is 50 thus 3x 3 = 9 This is the second interim answer.
The final answer is 2200 + 9 = 2209 ... Practice This one on paper first.

Trick 6 : Multiply any number by 11 .

Trick number 2 tells you how to multiply a two digit number by 11 but what if you have a number like 12345678. Well that is very easy if you our trick as given below. Read it carefully.

Let the number be 12345678 __ thus 12345678 x 11

Write down the number as 012345678 ( Add a 0 in the beginning)
Now starting from the units digit write down the numbers after adding the number to the right, so the answer will be 135802458

This one is simple if you think over it properly all you got to do is to add the number on the right . If you are getting a carry over then add that to the number on the left. So I will tell you how I got the answer . Read carefully. The number was 12345678 ___ I put a 0 before the number ____ so the new number 012345678 Now I wrote ___ 012345678

Then for the answer

8 + 0 = 8

7 + 8 = 15 (1 gets carry carried over)

6+1+7 = 14 ( 1 gets carried over)

5 + 1 + 6 = 12 ( 1 gets carried over)

4 + 1 + 5 = 10 ( 1 gets carried over)

3 + 1 + 4 = 8

2 + 3 = 5

1 + 2 = 3

0 + 1 = 1

Thus the answer = 135802458

Trick 7 : Square a 2 Digit Number, for this example 37:
Look for the nearest 10 boundary
In this case up 3 from 37 to 40.
Since you went UP 3 to 40 go DOWN 3 from 37 to 34.
Now mentally multiply 34x40
The way I do it is 34x10=340;
Double it mentally to 680
Double it again mentally to 1360
This 1360 is the FIRST interim answer.
37 is "3" away from the 10 boundary 40.
Square this "3" distance from 10 boundary.
3x3=9 which is the SECOND interim answer.
Add the two interim answers to get the final answer.
Answer: 1360 + 9 = 1369

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