MATHS TRICKS - IV

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Decimals Equivalents of Fractions
With a little practice, it's not hard to recall the decimal equivalents of fractions up to
10/11!

First, there are 3 you should know already:
1/2 = .5
1/3 = .333...
1/4 = .25

Starting with the thirds, of which you already know one:
1/3 = .333...
2/3 = .666...

You also know 2 of the 4ths, as well, so there's only one new one to learn:
1/4 = .25
2/4 = 1/2 = .5
3/4 = .75

Fifths are very easy. Take the numerator (the number on top), double it, and stick a
decimal in front of it.
1/5 = .2
2/5 = .4
3/5 = .6
4/5 = .8

There are only two new decimal equivalents to learn with the 6ths:
1/6 = .1666...
2/6 = 1/3 = .333...
3/6 = 1/2 = .5
4/6 = 2/3 = .666...
5/6 = .8333...

What about 7ths? We'll come back to them at the end. They're very unique.
8ths aren't that hard to learn, as they're just smaller steps than 4ths. If you have trouble
with any of the 8ths, find the nearest 4th, and add .125 if needed:
1/8 = .125
2/8 = 1/4 = .25
3/8 = .375
4/8 = 1/2 = .5
5/8 = .625
6/8 = 3/4 = .75
7/8 = .875

9ths are almost too easy:
1/9 = .111...
2/9 = .222...
3/9 = .333...
4/9 = .444...
5/9 = .555...
6/9 = .666...
7/9 = .777...
8/9 = .888...

10ths are very easy, as well. Just put a decimal in front of the numerator:
1/10 = .1
2/10 = .2
3/10 = .3
4/10 = .4
5/10 = .5
6/10 = .6
7/10 = .7
8/10 = .8
9/10 = .9

Remember how easy 9ths were? 11th are easy in a similar way, assuming you know your
multiples of 9:
1/11 = .090909...
2/11 = .181818...
3/11 = .272727...
4/11 = .363636...
5/11 = .454545...
6/11 = .545454...
7/11 = .636363...
8/11 = .727272...
9/11 = .818181...
10/11 = .909090...

As long as you can remember the pattern for each fraction, it is quite simple to work out the decimal place as far as you want or need to go!
Oh, I almost forgot! We haven't done 7ths yet, have we?
One-seventh is an interesting number:
1/7 = .142857142857142857...
For now, just think of one-seventh as: .142857
See if you notice any pattern in the 7ths:
1/7 = .142857...
2/7 = .285714...
3/7 = .428571...
4/7 = .571428...
5/7 = .714285...
6/7 = .857142...
Notice that the 6 digits in the 7ths ALWAYS stay in the same order and the starting digit
is the only thing that changes!

If you know your multiples of 14 up to 6, it isn't difficult to work out where to begin the
decimal number. Look at this:

For 1/7, think "1 * 14", giving us .14 as the starting point.
For 2/7, think "2 * 14", giving us .28 as the starting point.
For 3/7, think "3 * 14", giving us .42 as the starting point.
For 4/14, 5/14 and 6/14, you'll have to adjust upward by 1:
For 4/7, think "(4 * 14) + 1", giving us .57 as the starting point.
For 5/7, think "(5 * 14) + 1", giving us .71 as the starting point.
For 6/7, think "(6 * 14) + 1", giving us .85 as the starting point.

Practice these, and you'll have the decimal equivalents of everything from 1/2 to 10/11 at
your finger tips!

If you want to demonstrate this skill to other people, and you know your multiplication
tables up to the hundreds for each number 1-9, then give them a calculator and ask for a
2-digit number (3-digit number, if you're up to it!) to be divided by a 1-digit number.

If they give you 96 divided by 7, for example, you can think, "Hmm... the closest
multiple of 7 is 91, which is 13 * 7, with 5 left over. So the answer is 13 and 5/7, or:
13.7142857!"

Converting Kilometres to Miles
This is a useful method for when travelling between imperial and metric countries and
need to know what kilometres to miles are.
The formula to convert kilometres to miles is number of (kilometres / 8 ) X 5
So lets try 80 kilometres into miles
80/8 = 10
multiplied by 5 is 50 miles!
Another example
40 kilometres
40 / 8 = 5
5 X 5= 25 miles

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MATHS TRICKS- III

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Multiplying by 12 shortcut
So how does the 12's shortcut work?
Let's take a look.

12 X 7
the first thing is to always multiply the 1 of the twelve by the number we are multiplying
by, in this case 7. So 1 X 7 = 7.

Multiply this 7 by 10 giving 70.

Now multiply the 7 by the 2 of twelve giving 14. Add this to 70 giving 84.
Therefore 7 X 12 = 84

Let's try another:

17 X 12
Remember, multiply the 17 by the 1 in 12 and multiply by 10
(Just add a zero to the end):

1 X 17 = 17, multiplied by 10 giving 170.

Multiply 17 by 2 giving 34.

Add 34 to 170 giving 204.

So 17 X 12 = 204

lets go one more

24 X 12

Multiply 24 X 1 = 24. Multiply by 10 giving 240.

Multiply 24 by 2 = 48. Add to 240 giving us 288

24 X 12 = 288 (these are Seriously Simple Sums to do aren’t they?!)


Converting Kilos to pounds
In this section you will learn how to convert Kilos to Pounds, and Vice Versa.

Let’s start off with looking at converting Kilos to pounds. 86 kilos into pounds:

Step one, multiply the kilos by TWO.

To do this, just double the kilos.
86 x 2 = 172

Step two, divide the answer by ten.

To do this, just put a decimal point one place in from the right.
172 / 10 = 17.2

Step three, add step two’s answer to step one’s answer.

172 + 17.2 = 189.2
86 Kilos = 189.2 pounds

Let’s try:
50 Kilos to pounds:

Step one, multiply the kilos by TWO.

To do this, just double the kilos.
50 x 2 = 100

Step two, divide the answer by ten.

To do this, just put a decimal point one place in from the right.
100 / 10 = 10

Step three, add step two’s answer to step one’s answer.
100 + 10 = 110
50 Kilos = 110 pounds
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MATHS TRICKS -II

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Adding Time
Here is a nice simple way to add hours and minutes together:

Let's add 1 hr and 35 mins and 3 hr 55 mins together.


What you do is this:
make the 1 hr 35 mins into one number, which will give us 135 and do the same for the other number giving us 355

Now you want to add these two numbers together:

135
355
____
490

So we now have a sub total of 490. What you need to do to this and all sub totals is add the time constant of 40.

No matter what the hours and mins are, just add the 40 time constant to the sub total.

490 + 40 = 530

So we can now see our answer is 5 hrs and 30 mins!

Divisible by four

This little math trick will show you whether a number is divisible by four or not
So, this is how it works.

Let's look at 1234
Does 4 divide evenly into 1234?

Well for 4 to divide into any number we have to make sure that the last number is even. If it is an odd number, there is no way it will go in evenly.
So, for example, 4 will not go evenly into 1233 or 1235


So now we know that for 4 to divide evenly into any number the number has to end with an even number.

Back to the question...

4 into 1234

What you do is this:

Take the last number and add it to 2 times the second last number.

If 4 goes evenly into this number then you know that 4 will go evenly into the whole number.
So
4 + (2 X 3) = 10
4 goes into 10 two times with a remainder of 2 so it does not go in evenly.

Therefore 4 into 1234 does not go in completely.




Lets try 4 into 3436546
So, from our example, take the last number, 6 and add it to twice the penultimate number, 4

6 + (2 X 4) = 14
4 goes into 14 three times with two remainder.
So it doesn't go in evenly.


Let's try one more.

4 into 212334436

6 + (2 X 3) = 12
4 goes into 12 three times with 0 remainder.

Therefore 4 goes into 234436 evenly.
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MATHS TRICKS-I

Hello friends, here i am going to describe some vedic maths tricks to solve your aptitude sums easily. I am going to divide it in some parts. So here's first one.

How do we multiply by eleven easily?

First we will try this by writing the answer backwards.

So, when always multiplying a large number by 11, the last number will always be the last number of the sum we are multiplying.

Let me explain.

176 is the number we are multiplying.

So the last number in out answer will be 6. If the sum was 143 the last number in our answer would be 3... get it?

So now what?

Easy, just add the next number to the last number, 7 + 6 = 13

So the next last number will be 3, carry the 1.

Add the 7 and 1 together, giving 8, then add the carried 1, 9 then write that number as our next part of the answer, 936

Then, the last number will be the first number in our sum, in this case 1.

So the answer is 1936.

Try 278

Last number is 8

7 + 8 = 15

Second last number is 5, carry the 1

7 + 2 = 9 add the carried 1, 10

Third last number is 0, carry the 1

Add the carried 1 to the first number in the sum, 2 giving:

2 + 1 = 3

So the answer is 3058!

Alternatively, you could always just add a zero to the number you are multiplying and then add the original number to it again...

156 X 11

try it this way:

Add a zero to the end

1560

Add 156 to this

1560 + 156 = 1716

Whatever method works best, stick to it!

Temperature Conversion

This is a shortcut to convert Fahrenheit to Celsius and vice versa.

The answer you will get will not be an exact one, but it will give you an idea of the temperature you are looking at.

Fahrenheit to Celsius:

Take 30 away from the Fahrenheit, then divide the answer by two. This is your answer in Celsius.

Example:

74 Fahrenheit - 30 = 44. Then divide by two, 22 Celsius.

so 74 Fahrenheit = 22 Celsius.

Celsius to Fahrenheit just do the reverse:

Double it, then add 30.

30 Celsius double it, is 60, then add 30 is 90

30 Celsius = 90 Fahrenheit
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