i've taken this from vedic maths tutorials website.. i've been trying this so many times, and i kinda love this... why don't u hv a try on this... good luck!
Use the formula ALL FROM 9 AND THE LAST FROM 10 to perform instant subtractions.
For example 1000 - 357 = 643
We simply take each figure in 357 from 9 and the last figure from 10.
So the answer is 1000 - 357 = 643
And thats all there is to it!
This always works for subtractions from numbers consisting of a 1 followed by noughts: 100; 1000; 10,000 etc.
Similarly 10,000 - 1049 = 8951
For 1000 - 83, in which we have more zeros than figures in the numbers being subtracted, we simply suppose 83 is 083.
So 1000 - 83 becomes 1000 - 083 = 917
Using VERTICALLY AND CROSSWISE you do not need to the multiplication tables beyond 5 X 5.
Suppose you need 8 x 7
8 is 2 below 10 and 7 is 3 below 10.
Think of it like this:
The answer is 56.
The diagram below shows how you get it.
You subtract crosswise 8-3 or 7 - 2 to get 5,
the first figure of the answer.
And you multiply vertically: 2 x 3 to get 6,
the last figure of the answer.
That's all you do:
See how far the numbers are below 10, subtract one
number's deficiency from the other number, and
multiply the deficiencies together.
7 x 6 = 42
Here there is a carry: the 1 in the 12 goes over to make 3 into 4.
Here's how to use VERTICALLY AND CROSSWISE for multiplying numbers close to 100.
Suppose you want to multiply 88 by 98.
Not easy,you might think. But with
VERTICALLY AND CROSSWISE you can give
the answer immediately, using the same method
as above.
Both 88 and 98 are close to 100.
88 is 12 below 100 and 98 is 2 below 100.
You can imagine the sum set out like this:
As before the 86 comes from
subtracting crosswise: 88 - 2 = 86
(or 98 - 12 = 86: you can subtract
either way, you will always get
the same answer).
And the 24 in the answer is
just 12 x 2: you multiply vertically.
So 88 x 98 = 8624
This is so easy it is just mental arithmetic.
Multiplying numbers just over 100.
103 x 104 = 10712
The answer is in two parts: 107 and 12,
107 is just 103 + 4 (or 104 + 3),
and 12 is just 3 x 4.
Similarly 107 x 106 = 11342
107 + 6 = 113 and 7 x 6 = 42
Again, just for mental arithmetic
The easy way to add and subtract fractions.
Use VERTICALLY AND CROSSWISE to write the answer straight down!
Multiply crosswise and add to get the top of the answer:
2 x 5 = 10 and 1 x 3 = 3. Then 10 + 3 = 13.
The bottom of the fraction is just 3 x 5 = 15.
You multiply the bottom number together.
So:
Subtracting is just as easy: multiply crosswise as before, but the subtract:
A quick way to square numbers that end in 5 using the formula BY ONE MORE THAN THE ONE BEFORE.
752 = 5625
752 means 75 x 75.
The answer is in two parts: 56 and 25.
The last part is always 25.
The first part is the first number, 7, multiplied by the number "one more", which is 8:
so 7 x 8 = 56
Similarly 852 = 7225 because 8 x 9 = 72.
Method for multiplying numbers where the first figures are the same and the last figures add up to 10.
32 x 38 = 1216
Both numbers here start with 3 and the last
figures (2 and 8) add up to 10.
So we just multiply 3 by 4 (the next number up)
to get 12 for the first part of the answer.
And we multiply the last figures: 2 x 8 = 16 to
get the last part of the answer.
Diagrammatically:
And 81 x 89 = 7209
We put 09 since we need two figures as in all the other examples.
An elegant way of multiplying numbers using a simple pattern.
21 x 23 = 483
This is normally called long multiplication but
actually the answer can be written straight down
using the VERTICALLY AND CROSSWISE
formula.
We first put, or imagine, 23 below 21:
There are 3 steps:
a) Multiply vertically on the left: 2 x 2 = 4.
This gives the first figure of the answer.
b) Multiply crosswise and add: 2 x 3 + 1 x 2 = 8
This gives the middle figure.
c) Multiply vertically on the right: 1 x 3 = 3
This gives the last figure of the answer.
And thats all there is to it.
Similarly 61 x 31 = 1891
6 x 3 = 18; 6 x 1 + 1 x 3 = 9; 1 x 1 = 1
Multiply any 2-figure numbers together by mere mental arithmetic!
If you want 21 stamps at 26 pence each you can
easily find the total price in your head.
There were no carries in the method given above.
However, there only involve one small extra step.
21 x 26 = 546
The method is the same as above
except that we get a 2-figure number, 14, in the
middle step, so the 1 is carried over to the left
(4 becomes 5).
So 21 stamps cost £5.46.
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