Comments on: Quick Multiplication by 5

By: joolie

joolie — Mon, 28 Jan 2013 15:35:41 +0000

if sides are 4,3,5 …den according to ur formula p= 180/12 = 15..
angles are 4*15=60
3*15=45
5*15=75
but in real 4,3,5 is a right angle tringle..(4^2 + 3^2 = 5^2)..

By: priya

priya — Sun, 13 Jan 2013 15:45:33 +0000

I think there’s a alternative to the trick of multiplying by 5.

132/5
1/2 of 132 =66 and multiply by 10 which gives 660

133/5
1/2 of 133=66.5 and multiply by 10 which gives 665

Hence there is no need to remember the trick for even and odd numbers separately. Hope you agree with it . @vineet Patawari Sir

By: mahesh

mahesh — Thu, 16 Aug 2012 10:05:59 +0000

can you please send me some more tricks about the multiplication of any two numbers

By: santhakumar

santhakumar — Fri, 29 Jun 2012 06:06:21 +0000

I solved it by Venn diagram method.

By: FlameFletcher

FlameFletcher — Wed, 27 Jun 2012 14:18:15 +0000

Ok well let me submit something.
I hope you will like it vineet.
In a triangle.
we know the relation ship between sides and angles with trignometry.
but how can we find out angles if we know the sides in a simple method?
use ‘&’ as the proportionality symbol.
in a triangle ABC the side opposite to angleA is BC , side opposite to angleC is AB etc.
so as the side AB increases then angleC definitely increases. right?
so
AngleA & BC (& —> means directly proportional to)
AngleB & AC
AngleC & AB
Let ‘P’ be a constant.
AngleA = P(BC) —–> 1
AngleB = P(AC) ——>2
AngleC = P(AB) ——>3
Adding 1,2,3 we get……
AngleA+AngleB+AngleC = P(BC+AC+AB)
But AngleA+AngleB+AngleC = 180
therefore, 180= P(BC+AC+AB)
=> P= 180/(BC+AC+AB)
from formula if we know the 3 sides of a triangle we can find the constant ‘P’.
and to get an angle.
AngleA = P(BC)
so multiply P with a side opposite to the angle to get that angle.
here is an Example sum.
2,6,10 are the 3 sides of a triangle. Find out all their angles.
From my formula above, P = 180/(AB+BC+CA)
AB+BC+CA = 2+6+10 = 18
=> P=180/18
=10
therefore P=10 degrees per unit distance.
that means if there is an increase of 1 unit distance then the angle opposite to that side increases by 10 degrees.
AngleA = 10(BC) = 10(2) = 20 degrees
AngleB = 10(CA) = 10(6) = 60 degrees
AngleC = 10(AB) = 10(10)=100 Degrees
Therefore the angles are found.
Note: This formula can be used for any type of triangle and this formula is 100% usable and proved.
Note:The value of P is different for different triangles. So we always have to find P before finding angles.
Feel Free to use it and please publish this on this site.

By: manjusha

manjusha — Tue, 26 Jun 2012 13:37:14 +0000

@Santhakumar
from stmnt1+stmnt2 ie some boats are camels +all camels are tiles => some boats are tiles (cncln 2)

Now stmnt 1 can be converted into ‘some camels are boats ‘+ no boats is a soil(stmnt2) = some camels are not soils(concln 4) {I+E=O}

SO ANSWER IS 2 & 4.

By: Santhakumar

Santhakumar — Tue, 26 Jun 2012 10:55:56 +0000

How

By: manjusha

manjusha — Sat, 16 Jun 2012 05:36:18 +0000

i think u got 1 & 2 by ven method. can u depict it.

By: manjusha

manjusha — Sat, 16 Jun 2012 05:30:22 +0000

thank u sir

By: Santhakumar

Santhakumar — Fri, 15 Jun 2012 10:17:04 +0000

1&2