Multiplication by 11

We all know that it is easy to multiply a single digit number by 11. If you want to multiply 4 by 11, you simply repeat the digit for the answer, 44. If you multiply 6 by 11, you get 66.
Did you know it is easy to multiply two digit number by 11?
Multiplying a two-digit number by 11.
To multiply 16 by 11, add both the digits of the given number, 1+6 = 7. Now place this answer , 7, in between the two digits, in this case giving you 176.
16 X 11 = 176
These calculations are easy to do in your head. If somebody asks you to multiply 52 by 11, you could immediately say, "five hundred and seventy two".
That was easy! Now, what happens if the digits add to ten or more? comments

Finding age trick

Math tricks are a lot of fun. Students love them in the classroom. We are more open to learning when we are having fun in the process. Math teachers often use number tricks in the classroom to encourage enthusiasm among students. You can use some of these tricks with your friends as well.

A simple trick to find someone's age.
Step 1) Ask your friend to multiply the first number of his age by 5.
Step 2) Now ask him to add 3 to the result.
Step 3) Tell him to double this figure.
Step 4) Finally, ask him to add the second number of his age to the resulting figure and have him tell you the answer.
Step 5) Now you deduct 6 from the answer and you will have his age.

I am sure your friends will be impressed. comments

Number Trick

An interesting trick of number 421. What is so special about the number 421?
Number 421 is the smallest prime number formed by the powers of two in logical order from right to left.

Follow the given steps and you will notice an interesting loop of 4...2...1...
1) Select any whole number.
2) If it is an even number,divide by 2; If it is an odd number, multiply by 3 and add 1 to it.
3) Keep on repeating the process mentioned in step 2. We'll see that after a while the value 4,2,1 repeats itself.

Example: Lets pick a number, say, 23.

23 is an odd number; so multiply by 3 and add 1 to it;
(23 × 3) + 1 = 70
70 is an even number; so divide by 2;
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Funny Calculations

You can play this funny Math trick with your friends. Ask them to do the following calculations and you can predict their date of birth.
1) Add 18 to your Birth month.
2) Multiply by 25.
3) Subtract 333.
4) Multiply by 8.
5) Subtract 554.
6) Divide by 2.
7) Add your Birth date.
8) Multiply by 5.
9) Add 692.
10) Multiply by 20.
11) Add only the last two digits of your Birth year.
12) Subtract 32940 to get your complete date of birth.

Suppose the answer is 102382. This implies that your friend's date of birth is October 23, 1982 (MM/DD/YY).
(Note: If the answer is not right, your friend did not follow the directions correctly or lied about his Birthday.) comments

Fibonacci Numbers

The numbers in the following integer sequence are called the Fibonacci numbers.
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144…
By definition, the first two numbers in the Fibonacci sequence are 0 and 1, and each subsequent number is the sum of the previous two.
1 = 1+0
2 = 1+1
3 = 2+1
5 = 3+2
8 = 5+3
13= 8+5
21= 13+8
34= 21+13
55= 34+21

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Golden Spiral in Nature

"Nature hides her secrets because of her essential loftiness, but not by means of ruse".
~Albert Einstein

  

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Maths in Da Vinci's Art

Leonardo Da Vinci’s most famous illustration is the Vitruvian Man. The figure illustrates the Golden proportion (1:1.618), also known as the ‘Divine proportion’. The Vitruvian Man's drawing is based on the correlations of ideal human proportions. It is accompanied by notes based on the work of the famous first century Roman architect, Vitruvius. He was also the author of ‘De Architectura Libra X’; Vitruvius described the human figure, which was divinely created, as being the principal source of proportion. Leonardo’s drawing is traditionally named in honor of the architect. comments

The beautiful rectangle and the spiral

The Golden Spiral was first discovered by Pythagoras. The spiral is derived from the golden rectangle. When you connect a curve through the corners of these concentric rectangles, the golden spiral is formed.
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The Beauty Of A Rectangle

Look around, you see rectangular objects everywhere, for instance, computer screen, laptops, Desks, Books, Newspaper, cell phones, greeting cards, gift wrappers, paintings, calendars, doors, windows, closets, calculators, towels, bed sheets, photographs, color boxes, note books, dining table, mirrors, credit cards and the list goes on and on. Have you ever wondered why so many people have been drawing and building things that are rectangular shaped?

The ancient Greeks discovered that there is a specifically shaped rectangle that is most pleasing to the eye. It is not too thick, not too thin but just right. The rectangle possessing this characteristic is called the “Golden Rectangle”. If you simply draw what you believe to be the most beautiful rectangle, then measure the lengths of each side and finally divide the longest length by the shortest. You’ll probably find the ratio is somewhere around 1.6, which is called the golden ratio, rounded to the nearest tenth.
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Cool Multiplication

Here's an easy way to find out square of a two digit number.
I) Let's square a two digit number that ends in 5. (without using your calculator :))
For example, we would like to square the number 65.
Step 1: Multiply the first digit of a number with the next number that comes after it. In this case 7 comes after 6.
6x7=42
Step 2: Now place 25 after it.
4225

Well, 65X65 = 4225
By the way, 5 is my favourite number. What's yours?

II) Let's square any two digit number.
For example 27.
Step 1: Look for the nearest ten boundary, which is 30 (27+3=30).
Step 2: Now go down 3 numbers from 27.
=24
Step 3: Multiply 24X30 = 720 (answer 1)
Step 4: 27 is 3 from nearest ten boundary 30
Now square of 3 = 9 (answer 2)
Step 5: Add (answer1) and (answer2)
720+9 = 729

27X27 = 729 comments