MATH MAGIC
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Transcript of MATH MAGIC
![Page 1: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/1.jpg)
20 August 2013
MATH MAGIC
20 August 2013
![Page 2: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/2.jpg)
MULTIPLICATION TRICKS
![Page 3: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/3.jpg)
CROSS-MULPLICATION
14 X 12
![Page 4: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/4.jpg)
First, to get the last digit in the answer, multiply the two numbers on the right. Write the answer, as the rightmost digit in the problem’s answer.
![Page 5: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/5.jpg)
2x4=8
14 X 12
8
![Page 6: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/6.jpg)
Now, get the middle digit, cross-multiply both sets of numbers, and then add the together.
![Page 7: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/7.jpg)
1 x 2 = 21 x 4 = 4
6
14 X 12
68
![Page 8: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/8.jpg)
Lastly to get the last digit, simply multiply the left digits.
![Page 9: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/9.jpg)
1 x 1= 1 14 X 12
168
![Page 10: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/10.jpg)
TRY!
28 X 23In this case, we will do the carrying
procedure.
![Page 11: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/11.jpg)
COMPLEMENTARY MULTIPLICATION
96 x 94
![Page 12: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/12.jpg)
First, subtract both numbers in 100 and list the difference.
100 - 96 = 4 100 - 94 = 6
![Page 13: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/13.jpg)
Second step is to subtract diagonally. You will notice there that they will give the same answer, and this will be your base number.
![Page 14: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/14.jpg)
96 – 6 = 9094 – 4 = 90
![Page 15: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/15.jpg)
96 x 94
90
![Page 16: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/16.jpg)
Third, multiply the two numbers we got by figuring the difference between the original numbers and 100.
4 x 6 = 24
![Page 17: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/17.jpg)
•Lastly, write it to the right of the base number.
96 x 94
9,024
![Page 18: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/18.jpg)
•If the number are larger than 100, add the difference instead of subtracting.
Ex. 103
x 107
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103 – 100 = 3 107 – 100 = 7
103 + 7 = 110107 + 3 = 110
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•You will arrive with same answer then write it as the base number.
103 x 107
110
![Page 21: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/21.jpg)
•Multiply the 3 and 7, then write it as the base number.
3 x 7 = 21
![Page 22: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/22.jpg)
103 x 107
11,021
![Page 23: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/23.jpg)
This method is applicable also in numbers around 50.
Ex.
46 x 44
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MULTIPLYING BY 11
18X 11
![Page 25: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/25.jpg)
•Add the two digits and insert the sum between the digits.
1 + 8 = 9
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18 X 11
198
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99 X 11
In case that you got a two-digit number, add that numbers’ left digit to the digit in the original number.
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9 + 9 = 18
99 X 11
1,089
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SQUARING TRICKS
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Squaring a number around 100
If the number falls under 100 and above 50, you simply figure the difference between 100 and the number.
96²
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•Subtract the difference from the number being squared, and write the answer as the first digits in your answer.
100 – 96 = 4
![Page 32: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/32.jpg)
96² - 4
92 base number 92(00)
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•Take the difference between 100 and the number being squared and square.
100 – 96 = 44² = 16
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•Place that number after the base number and you have the answer.
96² = 9,216
![Page 35: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/35.jpg)
If the number to be squared is more than 100, add the difference to the number.
![Page 36: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/36.jpg)
Squaring numbers that ends in 5
Any number that ends in 5 is easy to square to start with, you know that
5 x 5 = 25, so the answer will automatically end in 25.
Ex. 35²
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•Add 1 to the first digit, ignore the rest at the number.
1 + 3(5)
4
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•Multiply the result to the first digit of the original number. This result is the first part of the answer.
4 x 3 = 12
![Page 39: MATH MAGIC](https://reader033.fdocuments.net/reader033/viewer/2022061111/54545132af795987748b8f6f/html5/thumbnails/39.jpg)
12 with 25 makes 1, 225.
Try! 85² 115²
65²
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SHORTCUT AND HELPFUL HINTS
18 X 101 = 1,81884 X 101 = 8,48497 X 101 = 9,797
102 X 101 = 10,302621 X 101 = 62,721
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Thank you!