Many of the people getting terrified on Mathematics.Here
some cool tricks to solve math problems easily and enhance your speed when you
calculate in your head.
The 11 Times Trick
1 . If we calculate
52 x 11, Take the original number and imagine space between both numbers,
5____2 Now add
both numbers (5+2=7) and put it in that space. 5—(5+2)-2=572
2 . If the numbers in
the middle add up to a 2 digit number, just insert the second number and add 1
to the first: If we calculate 47 X 11, 4_____7 Now add both numbers (4+7=11)
and put it in that space.
(4+1)-(1)-7=517
Quick Square If we
square two numbers ending with 5, We can solve it easily using this trick.
Mulitply
the first digit by
itself + 1, and put 25 on the end. Thats all!
25 x 25 2(2 + 1)—5 x 5 2 x 3—25 625
Multiply by 5
This trick is super
easy for solving complex questions.
1 . Take any number,
then divide it by 2 (in other words, halve the number). If the result is whole,
add a 0 at the end. If it is not, ignore the remainder and add a 5 at the end.
2682 x 5 = (2682 / 2)
& 5 or 0 2682 / 2 = 1341 (whole number so add 0) 13410 Let’s try
another:5887 x 5
2943.5 (fractional
number (ignore remainder, add 5) 29435
Few
Tricks Which Will Help Solving Numerical Aptitude Question Quickly …
TRICK 1 :- related to square of number 9
(9)² = 81
(99)² = 9801
(999)² = 998001
(99….n no.s of 9) to the power 2 = (n-1)9’s followed by 8 then (n-1)0’s followed
by 1
so by the trick :: (99999)² = 9999800001
TRICK 2 :- how to find square of
any no.
(2)² = 4
(11)² = 121
(12)² = 144
(123)² = 15129
the trick is take the unit digit no. as ‘a’
and the remaining digits as ‘b’ and use the formula b² 2ab a²
example
:: 12² = take a=2 and b=1
so start from right hand side
a² =4
2ab =4
b²=1
so putting in the sequence we have 144
next for (123)² take a=3,b=12
now , a²=9
2ab = 72 (so we keep 2 and carry 7) =2
b²=144 (+ carry 7 ) = 151
so when we put in the sequence we get 15129
TRICK 3:- To calculate square of
two digit numbers... From 26 to 50:-
(if you remember the square of the no. from 1
to 25)
trick:- square of x (x= 26 to 50) = (x-25)/
(50-x)square
ex.- square of 46 = (46-25)/(50-46)square =
21/16= 2116 Ans.
square of 42 = (42-25)/(50-42)square = 17/64=
1764
square of 37 = (37-25)/(50-37)square = 12/
169= 1369(take last two digits only, rest in reminder)
square of 29 = (29-25)/ (50-29)square = 4/441
= 841
To Find Square Of A 3 Digit
Number :
LET THE NUMBER BE XYZ SQ (XYZ) is calculated like this
STEP 1. Last digit = last digit of SQ (Z)
STEP 2. Second Last Digit = 2YZ + any
carryover from STEP 1.
STEP 3. Third Last Digit 2XZ+ Sq + any
carryover from STEP 2.
STEP 4. Fourth last digit is 2XY + any
carryover from STEP 3.
STEP 5 . In the beginning of result will be
Sq(X) + any carryover from Step 4.
EXAMPLE : SQ (431)
STEP 1. Last digit = last digit of SQ (1) =1
STEP 2. Second Last Digit = 231 + any carryover from STEP 1.= 6
STEP 3. Third Last Digit 241+ Sq (3) + any carryover from STEP 2.= 241 +9= 17. so 7 and 1 carryover
STEP 4. Fourth last digit is 243 + any
carryover (which is 1) . = 24+1=25. So 5 and carry over 2.
STEP 5 . In the beginning of result will be
Sq(4) + any carryover from Step 4. So 16+2 =18.
So the result will be 185761.
If the option provided to you are such that
the last two digits are different, then you need to carry out first two steps
only , thus
saving time. You may save up to 30 seconds on
each calculations and if there are 4 such questions you save 2 minutes which
may really affect UR Percentile score.
Shortcut Techniques
For Percentage
Shortcut 1:If we
increased any value by x % and then decreased by y %. Then the resulting effect
in percent will be:“+ x + y + xy /100”.
Various Examples related to this Percentage Short cuts are
given below:
Example 1:The price
of goods is marks 20% more than the real price by the shopkeeper. After that
the shopkeeper allowed a discount of 10%. Now What profit or loss did the
shopkeeper will get?
Solution:We solve
this as follow by using the percentage shortcut1 as follow:
The Loss (or) Profit
he will get is = 20 – 10 + (+20)(-10)/100 =+ 8% (profit).
Example 2:Side of the
square is increased by 30%. Find the percentage increase in area.
Solution:Here we
again use the percentage shortcut 1.
So the increased area
percentage = 30 + 30 + (30)(30)/100 =69 % (increased).
Example 3:Radius of
the circle is decreased by 20%. What will be the percent change in area of the
circle?
Solution:Therefore by
using thepercentage shortcut1:
The Percent change in
area of circle is= - 20 - 20 + (-20)(-20)/100 =-36% (decreased)
Example 4:The price
of a car is increased by 15% than after that again decreased by 15%. What will
be the percent change?
Solution:The percent
change is = + 15 - 15 + (+15)(-15)/100 =- 2.25 % (decreased)
Example 5:Length of a
rectangle is increased by 40% and breadth of the rectangle is decreased by 40%.
Find change in area.
Solution:By using the
formula of percentage shortcut given above:
The percent change in
area of rectangle is= 40 - 40 + (-40)(+40)/100 =-16 %( decreased)
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