Basic Maths made easy-Speed Enhancing Tips
Mathematics the base every engineering branch,is used not only by engineers,but by economists,historians,teachers…infact everyone need maths in there everyday life.And because of this importance of arithmetics almost every competitive exams test your maths skills.In most cases they test not only your skill but also your ability to use right thing at the right place.In big exams like CAT,XAT, GMAT etc if we try answering the quatitative questions after the exam it will look easier to us.So the key in such exam is SWIFT thinking,and small tricks.Conventional maths is a bit time consuming.So here are a few simple tricks which may help you in simple addition and multiplications.
Multiplication
Usually multiplication is considered a tough job as the number of digits goes high but here we will do this in single step whether the number is 2 or 3 or 4 digit. Its better I explain with an example or else it will be confusing.
Two digit numbers:
a b *
x y
a * x+$, a * y+b * x+$, b * y
Let ab and xy are the two numbers to be multiplied. It’s a three step process which is explained below. You will get the answer by removing the commas. “$” symbol indicates a carry over from previous position, which can be zero also. This equation may sound weird but just throw a look at the example below.
E.g.:-
28*
67
Start from the unit place (b*y) place 8*7=56. (6 goes towards answer and $=5)
Now (a*y+b*x+$) means 2*7 + 8*6 + 5 = 67
(Here 7 moves to answer and $ = 6 now).
Final step (a*x+$) means 2*6 + 6 = 18
So the answer is 1876.
The whole thing may look very disturbing to you but let me tell you this trick is worth trying. Give it a few minutes, it will be surely useful.
Three digit numbers:
In 3 digit numbers it is a 5 step process. An example will do the explanation job.
abc*
xyz
a*x+$, a*y+b*x+$, a*z+c*x+b*y+$, b*z+c*y+$, c*z
If you understood previous trick of 2digit multiplication then you will surely understand this one also. Anyway I will explain with an example.
E.g.:-
123*
789
I will simply write down the procedure.
Step1: Start from unit place 9*3=27, CARRY=2 ANS=7
Step2: 2*9+3*8 + CARRY =44, CARRY=4 ANS=47
Step3: 1*9+3*7+2*8+ CARRY=50, CARRY=5 ANS=047
Step4: 1*8+2*7+ CARRY=27, CARRY=2 ANS=7047
Step5: 1*7+ CARRY=9 ANSWER=97047
Another Multiplication technique(Reference Number )
This is used when the numbers to be multiplied is in a closer range.
E.g.:-
17*
14
Let “10” be your ref. Number.
7 & 4 are the deviation from the ref number. Add any one of this two the other number. Like 17+4 or 14+7, both will give you same result 21.Now this sum * ref. number + product of deviations will give you the result.
21*10+ (7*4) =238
E.g.:-
25*17=?
Take 20 as ref number. So deviations are 5,-3.
(17+5)*20+ (5*-3) =440-15=425.
Multiplication
Usually multiplication is considered a tough job as the number of digits goes high but here we will do this in single step whether the number is 2 or 3 or 4 digit. Its better I explain with an example or else it will be confusing.
Two digit numbers:
a b *
x y
a*x+$, a*y+b*x+$, b*y
Let ab and xy are the two numbers to be multiplied. It’s a three step process which is explained below. You will get the answer by removing the commas. “$” symbol indicates a carry over from previous position, which can be zero also. This equation may sound weird but just throw a look at the example below.
E.g.:-
28*
67
Start from the unit (b*y) place 8*7=56. (6 goes towards answer and $=5)
Now (a*y+b*x+$) means 2*7 + 8*6 + 5 = 67
(Here 7 moves to answer and $ = 6 now).
Final step (a*x+$) means 2*6 + 6 = 18
So the answer is 1876.
The whole thing may look very disturbing to you but let me tell you this trick is worth trying. Give it a few minutes, it will be surely useful.
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