hey everyone what is 79 x 11 what is 4%
of 250 what is the sum of all even
numbers from zero to hundred seven nine
alpha beta gamma oh Math but don't worry
in today's video I'm going to give you
some math tricks to help you solve all
these problems really quick so today I'm
going to give you five math tricks and
three tips from renowned mathematicians
to help you become the wizard of
mathemagic. So hey this is
Chetna and you're watching ChetChat and
today's episode is sponsored by Cuemath
and after school math excellence based
program with both home based centers and
an online portal for students from kg to
10th standard Cuemath is one of India's
largest dedicated math learning program
and the focus is to build the
foundations of math with a unique
curriculum and teaching methodology
that's designed by experts from IIT and
the University of Cambridge now what's
really exciting is that you're getting a
free demo class and the link is given in
the description box below so click on
that link get yourself a free trial
class and if you enroll you get a 10%
discount on the package and now let's
get going with the five math tricks for
fast calculation trick number one is
called estimation so so many times we
walk into a restaurant when it says 12%
off or we walk into a store and it
announces 30% off and we're freaking
out that what does it exactly mean so
how about we learn a quick trick of how
to estimate mentally right there in the
store or the restaurant so what is four
percent of 250 now Before we jump into
the answer how about we try estimating
that answer let's take ten percent of
250 and ten percent would
25 right we all know that now what is 1%
of 250 that would mean 2.5 and if we
want 4% then it's 4 times of 1% which is
four times of 2.5 which is 10
okay let's try another exercise in
estimation now before you start adding
all these big numbers let's try to take
them to the nearest hundred so I would
take 988 up to thousand and I would take
880 up to 900 and I would add them up
and I would get 1,900 now how much have
I added here in order to get a thousand
I've added 12 to 988 and I've added 20
to 880 to get 900 so I need to subtract
this 32 from 1900 and I get 1868 wasn't
that easy
tip number one visualize don't memorize
so Albert Einstein once said that Pure
math is actually like a poetry of
logical reasoning so don't look at math
as cramming up all those formulae
instead look at it like a storybook or a
pattern and that'll help you enhance
your logical reasoning
okay so what is the sum of all even
numbers from zero to hundred okay let's
break that down what is the sum of all
even numbers from zero to ten now there
are four even numbers between zero and
ten which are two four six and eight
let's visualize these numbers so two
let's draw two and if I take four it's
one two three four and if I take six
it's one two three four five six and if
I take eight it's one two three four
five six seven eight so what have I got
here is a rectangle of 4 into 5 which is 20
and now you can begin to guess the
formula it's the number of even numbers
between 0 and 10 so in this case it's 4 even numbers between 0 and 10
multiplied by n plus 1 that is 5 which
is equal to 20 now try it with odd
numbers it's not exactly this formula
it's something different and I want you
to put that formula in the comment
section below what is the sum of the odd
numbers between 0 and 10 and what did
you get as a formula
and before we get to the balance three
tricks don't forget to tell me which of
these tricks was your favorite or if
there's any other trick that you love
put everything down for me in the
comment section below this video
trick number three division by five what
is 25 by 5= 5 that's easy but what is 2 3
4 1 by 5 hmm okay let's remember 5 is 10
by 2 so how about we first divide this
by 10 so 2 3 4 1 divided by 10 is 234.1 and now I can multiply this by 2 and
I've got four sixty eight point two
wasn't that quick okay and now's your
turn eight hundred and ninety seven by five the fastest calculation in the comment box
right now tip number two
strengthen your fundamentals Eric Temple
Bell of famous Scottish mathematician
once said that obvious is the most
dangerous word in mathematics so go back to basics strengthen your fundamentals
and practice practice practice to become
this expert slowly and gradually okay
now a very simple trick trick number
four is multiplication by eleven and I'm
going to take a very basic example right
now to explain this let's take 43 into
11 and when we multiply the unit's place
is this the first digit is this and the
digit in the middle is the sum of these
two 473 now that sounds too easy so
let's take a little complicated example
to see if that really works okay we've
got a bigger number here 346 by 11 let's
see how it goes so the unit's place is
six the first digit is 3 now the number
here is the sum of
two digits which is ten so I put a zero
here and I keep the one for carry
forward and the number here is the sum
of these two digits which is seven and
so the answer is three eight zero six
this formula works fail proof you just
need to be careful about doing the carry
forward every time now before we move on
to the next step
I wanted to remind you that we have a
video called the five tips to score a
hundred percent in math and I'm dropping
a link for you in the description box so
you can go check that out
once you've finished watching this video
and trick number five is to find the
square of any number ending in five this
magical trick will help you find the
square at lightning speed so what is the
square of 85 quick write it down in the
comment section right now did you get
seven two to five if you didn't here's
how we got it so 85 into 85 now the last
two digits will always be 25 the square
of 5 is 25 and the first two digits will
be 8 into the number that comes after 8
which is 9 so 8 into 9 is 72 and you've
got 7 to 2 finds let's try this with 105
so 105 a square and like I said the last
two digits will always be the square of
5 which is 25 and the first few digits
will be 10 into you're right 11 so 11025
isn't that lightning speed okay so now
that we've learned these five tricks for
fast calculation remember that math is
much more than just fast calculation it
needs logical reasoning the right
mindset and above all lots and lots of
practice
and meantime press the subscribe button
and the Bell icon right next to it and
give us a thumbs up so we can make more
math videos for you and happy watching
