HERE WE ARE NOT DOING MATH BUT MAKING SOME TRICKY TECHNIQUES THAT ARE VERY IMPORTANT WHEN WE HAVE TO DO A LOT OF MATHEMATICS WITHIN VERY CONSTRAIN TIME. SO TRY TO REMEMBER AND ENJOY THE TRICKS.......
# There are 25 prime numbers from 1-100. If you can remember the sequence like following technique then you can speedy calculate prime numbers from any range like 31-70, 36-83, etc.
1-10=4
11-20=4
21-30=2
31-40=2
41-50=3
51-60=2
61-70=2
71-80=3
81-90=2
91-100=1
Shortcut:
2- 322,
3- 321.
The factors of 6 is : 1,2,3 and 6.
The multiple of 6 is : 6,12,18,24.......
On the other hand according to Barron's GRE book,
The factors of 6 is : 1,2,3 and 6. Again,
-1,-2,-3,-6.
The multiple of 6 is : 6,12,18,24.......
Again,
-6,-12,-18,-24.....
# Always remember that 1 is not a prime number.
# Always remember that 0 is also a integer but it is neither positive nor negative.
# Want to remember the sequence of Roman numbers?
I =1
V =5
X =10
Everybody knows these three numbers. Now,
L
=50
C =100 (Century)
D = 500
M =1000
(Millennium)
The technique to remember the sequence is LCD Monitor. Ok.
# If you can remember the root over of 2= 1.41 and root over of 3= 1.73 then you can speedy calculate any math which have root over of 2 or root over of 3.
# If 4th December of 2008 is Monday then 4th December of 2009 is what ?
- Technique: 365/7 = 52 weeks and 1 day so the answer is Tuesday.
In the case of leap year the answer will Wednesday. ( Leap year will calculate if the stipulated range of time contain Leap year February).