Don’t Solve are Smart Math problems attempted without solving. By using simple logic and smart techniques, answers to seemingly complex Math problems can be easily found in a matter of seconds… without actually solving the problem! Don’t believe it? Read below to see it for yourself!
Anyone can benefit by learning better Math. Whether you are a student, a parent, a teacher or simple a casual Internet surfer, this will change your outlook for Math – guaranteed! Whether you are taking any Math test or even training others for a Math test, these Math techniques will boost your confidence as well as the score. Don’t take GRE, GMAT, SAT or any other similar test without LazyMaths.com. Our students have reported significant increase in their quant scores in these tests.
Every week we publish 1 FREE Don’t Solve problem. To learn all the hundreds of math techniques, sign up with LazyMaths.com. When you sign up and become a member, you can access math techniques in Algebra, Geometry, Ratio Proportion, Averages, Time Speed & Distance and many more areas. You can also interact with other users, leave comments, ask questions and rate every problem!
Here is this week’s FREE Don’t Solve problem…
Problem
Find the value of ‘a’ in .
a.4
b.2
c.1
d.3
e.0
Usual Method
() = 12
= 1
a = 0
(Ans: e)
Estimated Time to arrive at the answer = 75 seconds.
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Smart Technique
Simply look at the options and start substituting the values in the expressions and just check which one satisfies the equation Also, remember to start substituting with the value that is easiest of all to substitute. In this case, for example, the easier values are ‘0’ and ‘1’. You would notice that ‘0’ satisfies the equation as follows:
Hence option ‘e’.
(Ans: e)
Estimated Time to arrive at the answer = 10 seconds.
Tell us what you think about the techniques used to solve this problem. Does this help in making math easy? Save time?
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NOTE: We publish one FREE problem every Wednesday. It auto expires after 1 month. Become a Member to learn hundreds of shortcuts and techniques.
Zappers are Speed Math shortcuts that help solve seemingly complex Math problems in a matter of seconds… without using a calculator!
Anyone can benefit by learning better Math. Whether you are a student, a parent, a teacher or simple a casual Internet surfer. This will change your outlook for Math – guaranteed! Whether you are taking any Math test or even training others for a Math test, these Math shortcuts will boost your confidence as well as score. Don’t take GRE, GMAT, SAT or any other similar test without LazyMaths.com. Our students have reported significant increase in their quant scores in these tests.
Every week we publish 1 FREE Zapper. To learn all the hundreds of math shortcuts, sign up with LazyMaths.com. When you sign up and become a member, you can access hundreds of math shortcuts, download practice sheets, leave comments, ask questions and rate every shortcut!
Here is this week’s FREE Zapper…
Tell us what you think about this shortcut. Does this help in making math easy? Save time?
Feel free to suggest any new shortcuts or share your comments. If you like this site, share it with your friends.
NOTE: We publish one FREE shortcut every Sunday. It auto expires after 1 month. Become a Member to learn hundreds of shortcuts and techniques.
Don’t Solve are Smart Math problems attempted without solving. By using simple logic and smart techniques, answers to seemingly complex Math problems can be easily found in a matter of seconds… without actually solving the problem! Don’t believe it? Read below to see it for yourself!
Anyone can benefit by learning better Math. Whether you are a student, a parent, a teacher or simple a casual Internet surfer, this will change your outlook for Math – guaranteed! Whether you are taking any Math test or even training others for a Math test, these Math techniques will boost your confidence as well as the score. Don’t take GRE, GMAT, SAT or any other similar test without LazyMaths.com. Our students have reported significant increase in their quant scores in these tests.
Every week we publish 1 FREE Don’t Solve problem. To learn all the hundreds of math techniques, sign up with LazyMaths.com. When you sign up and become a member, you can access math techniques in Algebra, Geometry, Ratio Proportion, Averages, Time Speed & Distance and many more areas. You can also interact with other users, leave comments, ask questions and rate every problem!
Here is this week’s FREE Don’t Solve problem…
Problem
3 men and 6 women can dig a well in 4 days. 5 men and 4 women take 3 days. How many days would 8 women and 1 man take?
a.6 days
b.8 days
c.10 days
d.4 days
e.9 days
Usual Method
Let ‘m’ be the fraction be the amount of work done by 1 man in 1 day and ‘w’ be the fraction of work done by 1 woman in 1 day.
3m + 6w = 1/4
12 m + 24 w = 1 …… Eq. 1.
Similarly,
5m + 4w = 1/3
15m + 12w = 1 …… Eq. 2.
Solving both equation 1 and 2 simultaneously we get
18m = 1 and 72w = 1
m = and w =
8w + 1m =
Hence, 6 days.
(Ans: a)
Estimated Time to arrive at the answer = 120 seconds.
Smart Technique
If 3 men and 6 women take 4 days, hypothetically, 1.5 men and 3 women will take 8 days. Hence, 1 man and 8 women will obviously take less than 8 days. Also, 1 man and 8 women will also take more than 4 days; hence the answer lies between 8 days and 4 days i.e. 6 days.
(Ans: a)
Estimated Time to arrive at the answer = 5 seconds.
Tell us what you think about the techniques used to solve this problem. Does this help in making math easy? Save time?
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NOTE: We publish one FREE problem every Wednesday. It auto expires after 1 month. Become a Member to learn hundreds of shortcuts and techniques.
Zappers are Speed Math shortcuts that help solve seemingly complex Math problems in a matter of seconds… without using a calculator!
Anyone can benefit by learning better Math. Whether you are a student, a parent, a teacher or simple a casual Internet surfer. This will change your outlook for Math – guaranteed! Whether you are taking any Math test or even training others for a Math test, these Math shortcuts will boost your confidence as well as score. Don’t take GRE, GMAT, SAT or any other similar test without LazyMaths.com. Our students have reported significant increase in their quant scores in these tests.
Every week we publish 1 FREE Zapper. To learn all the hundreds of math shortcuts, sign up with LazyMaths.com. When you sign up and become a member, you can access hundreds of math shortcuts, download practice sheets, leave comments, ask questions and rate every shortcut!
Here is this week’s FREE Zapper…
Tell us what you think about this shortcut. Does this help in making math easy? Save time?
Feel free to suggest any new shortcuts or share your comments. If you like this site, share it with your friends.
NOTE: We publish one FREE shortcut every Sunday. It auto expires after 1 month. Become a Member to learn hundreds of shortcuts and techniques.
Don’t Solve are Smart Math problems attempted without solving. By using simple logic and smart techniques, answers to seemingly complex Math problems can be easily found in a matter of seconds… without actually solving the problem! Don’t believe it? Read below to see it for yourself!
Anyone can benefit by learning better Math. Whether you are a student, a parent, a teacher or simple a casual Internet surfer, this will change your outlook for Math – guaranteed! Whether you are taking any Math test or even training others for a Math test, these Math techniques will boost your confidence as well as the score. Don’t take GRE, GMAT, SAT or any other similar test without LazyMaths.com. Our students have reported significant increase in their quant scores in these tests.
Every week we publish 1 FREE Don’t Solve problem. To learn all the hundreds of math techniques, sign up with LazyMaths.com. When you sign up and become a member, you can access math techniques in Algebra, Geometry, Ratio Proportion, Averages, Time Speed & Distance and many more areas. You can also interact with other users, leave comments, ask questions and rate every problem!
Here is this week’s FREE Don’t Solve problem…
Problem
In an alloy of three metals A, B and C, the quantity of metal A is 4/5th of B and that of B is 3/4th of C. What is the quantity in lb of each metal in 47 lbs of the alloy? (In the order of A, B and C.)
a.13, 22, 12
b.12, 13, 22
c.12, 15, 20
d.20, 15, 12
e.10, 20, 18
Usual Method
A = 4/5 B B = 3/4 C
5A = 4B 4B = 3C
A : B = 4 : 5 B : C = 3 : 4
A : B : C
4 : 5
3 : 4
12 : 15 : 20
Also, 12 + 15 + 20 = 47 lbs
Hence, A = 12 lbs, B = 15 lbs and C = 20 lbs.
(Ans: c)
Estimated Time to arrive at the answer = 60 seconds.
Smart Technique
The first step is to eliminate those options whose sum 47. Thus option ‘e’ is eliminated as sum of 10 + 20 + 18 = 48.
The next step is to identify the metal with maximum or minimum quantity. Because A = 4/5 B and B = 3/4 C; the metal C is of maximum quantity and A is of minimum quantity. Thus options ‘a’ and ‘d’ are eliminated. This leaves us with options ‘b’ and ‘c’ only. Since, A = 4/5 B; 5A = 4B.
For option ‘b’, 5 x 12 4 x 13, hence ‘b’ is also eliminated. Thus answer is option ‘c’.
(Ans: c)
Estimated Time to arrive at the answer = 15 seconds.
Tell us what you think about the techniques used to solve this problem. Does this help in making math easy? Save time?
Feel free to suggest any new shortcuts or share your comments. If you like this site, share it with your friends.
NOTE: We publish one FREE problem every Wednesday. It auto expires after 1 month. Become a Member to learn hundreds of shortcuts and techniques.
Zappers are Speed Math shortcuts that help solve seemingly complex Math problems in a matter of seconds… without using a calculator!
Anyone can benefit by learning better Math. Whether you are a student, a parent, a teacher or simple a casual Internet surfer. This will change your outlook for Math – guaranteed! Whether you are taking any Math test or even training others for a Math test, these Math shortcuts will boost your confidence as well as score. Don’t take GRE, GMAT, SAT or any other similar test without LazyMaths.com. Our students have reported significant increase in their quant scores in these tests.
Every week we publish 1 FREE Zapper. To learn all the hundreds of math shortcuts, sign up with LazyMaths.com. When you sign up and become a member, you can access hundreds of math shortcuts, download practice sheets, leave comments, ask questions and rate every shortcut!
Here is this week’s FREE Zapper…
Tell us what you think about this shortcut. Does this help in making math easy? Save time?
Feel free to suggest any new shortcuts or share your comments. If you like this site, share it with your friends.
NOTE: We publish one FREE shortcut every Sunday. It auto expires after 1 month. Become a Member to learn hundreds of shortcuts and techniques.
Don’t Solve are Smart Math problems attempted without solving. By using simple logic and smart techniques, answers to seemingly complex Math problems can be easily found in a matter of seconds… without actually solving the problem! Don’t believe it? Read below to see it for yourself!
Anyone can benefit by learning better Math. Whether you are a student, a parent, a teacher or simple a casual Internet surfer, this will change your outlook for Math – guaranteed! Whether you are taking any Math test or even training others for a Math test, these Math techniques will boost your confidence as well as the score. Don’t take GRE, GMAT, SAT or any other similar test without LazyMaths.com. Our students have reported significant increase in their quant scores in these tests.
Every week we publish 1 FREE Don’t Solve problem. To learn all the hundreds of math techniques, sign up with LazyMaths.com. When you sign up and become a member, you can access math techniques in Algebra, Geometry, Ratio Proportion, Averages, Time Speed & Distance and many more areas. You can also interact with other users, leave comments, ask questions and rate every problem!
Here is this week’s FREE Don’t Solve problem…
Problem
If means ; find the value of 3.124*1.39.
a.2.41324
b.3.24026
c.4.00236
d.2.41026
e.2.313456
Usual Method
Substituting the values of ‘x’ and ‘y’ according to the data given, we get
i.e.
= 2.41026
(Ans: d)
Estimated Time to arrive at the answer = 90 seconds as this is a calculation intensive problem.
Smart Technique
Just get to the ‘’ level. Note that the product of these two numbers should be 2+3 = 5 digits after the decimal point. This eliminates option ‘e’.
Also, the product of the last digits is ‘6’ (9 x 4 = 36). Hence, ‘6’ should be the last digit of the answer. This eliminates option ‘a’.
Also, note that 13 x 17 > 200. Hence, the answer should be a number starting with 2.something…
Hence, the answer is option ‘d’.
(Ans: d)
Estimated Time to arrive at the answer = 10 seconds
Tell us what you think about the techniques used to solve this problem. Does this help in making math easy? Save time?
Feel free to suggest any new shortcuts or share your comments. If you like this site, share it with your friends.
NOTE: We publish one FREE problem every Wednesday. It auto expires after 1 month. Become a Member to learn hundreds of shortcuts and techniques.
Zappers are Speed Math shortcuts that help solve seemingly complex Math problems in a matter of seconds… without using a calculator!
Anyone can benefit by learning better Math. Whether you are a student, a parent, a teacher or simple a casual Internet surfer. This will change your outlook for Math – guaranteed! Whether you are taking any Math test or even training others for a Math test, these Math shortcuts will boost your confidence as well as score. Don’t take GRE, GMAT, SAT or any other similar test without LazyMaths.com. Our students have reported significant increase in their quant scores in these tests.
Every week we publish 1 FREE Zapper. To learn all the hundreds of math shortcuts, sign up with LazyMaths.com. When you sign up and become a member, you can access hundreds of math shortcuts, download practice sheets, leave comments, ask questions and rate every shortcut!
Here is this week’s FREE Zapper…
Tell us what you think about this shortcut. Does this help in making math easy? Save time?
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After the most successful and very useful article on THE ULTIMATE GUIDE TO NUMBER CLASSIFICATION, LazyMaths.com is pleased to offer another path breaking article – THE ULTIMATE COLLECTION OF EVERY KNOWN TESTS OF DIVISIBILITY.
As a part of any speed math exam like GMAT, GRE or CAT, if you are trying to find out whether that number is evenly divisible without actually dividing it, then use these tests of divisibility. Learn these tests and save yourself precious time.
Divisor
Divisibility condition
Examples
1
Automatic
Every number is divisible by 1
2
The last digit is even (0,2,4,6 or 8 )
1294: 4 is even
3
The sum of digits is divisible by 3.
405: 4 + 0 + 5 = 9, which clearly is divisible by 3.
4
The number formed by the last two digits is divisible by 4.
40832: 32 is divisible by 4.
5
The last digit is 0 or 5.
490: the last digit is 0.
6
It is divisible by 2 and 3.
1,458: 1 + 4 + 5 + 8 = 18, 1 + 8 = 9, so it is divisible by 3 and the last digit is even, hence number is divisible 6.
7
If you double the last digit and subtract it from the rest of the number and the answer is divisible by 7.
483: 48 – (3 × 2) = 42 = 7 x 6.
8
The number formed by the last three digits is divisible by 8.
56: (5 × 2) + 6 = 16.
9
The sum of digits is divisible by 9.
2,880: 2 + 8 + 8 + 0 = 18: 1 + 8 = 9.
10
The number ends in 0.
130: the last digit is 0.
11
If you sum every second digit, and subtract all the other digits, the answer is divisible by 11.
918,082: 9 – 1 + 8 – 0 + 8 – 2 = 22.
12
The number is divisible by 3 and 4.
324: (32 × 2) − 4 = 60.
13
Add 4 times the last digit to the rest, the answer is divisible by 13.
637: 63 + (7 × 4) = 91, 9 + (1 × 4) = 13.
14
It is divisible by 2 and 7
224: it is divisible by 2 and by 7.
15
It is divisible by 3 and 5
390: it is divisible by 3 and by 5.
16
Sum the number with last two digits removed, times 4, plus the last two digits.
176: (1 × 4) + 76 = 80.
17
Subtract 5 times the last digit from the rest, the answer is divisible by 17.
221: 22 – (1 × 5) = 17.
18
It is divisible by 2 and 9.
342: it is divisible by 2 and by 9.
19
Add twice the last digit to the rest, the answer is divisible by 19.
437: 43 + (7 × 2) = 57.
20
The number formed by the last 2 digits is divisible by 20.
The number formed by the last two digits is divisible by 25.
134,250: 50 is divisible by 25.
27
Since 37×27=999; the multiplier is one, taking three digits at-a-time. Sum the digits in blocks of three from right to left.
2,644,272: 2 + 644 + 272 = 918.
Subtract 8 times the last digit from the rest.
621: 62 − (1×8) = 54.
29
Add three times the last digit to the rest.
261: 1×3=3; 3+26= 29
31
Subtract three times the last digit from the rest.
32
The number formed by the last five digits is divisible by 32, as follows:
If the ten thousands digit is even, examine the number formed by the last four digits.
41,312: 1312.
If the ten thousands digit is odd, examine the number formed by the last four digits plus 16.
254,176: 4176+16 = 4192.
Add the last two digits to 4 times the rest.
1,312: (13×4) + 12 = 64.
33
Add 10 times the last digit to the rest.
627: 62 + 7 x 10 = 132, 13 + 2 x 10 = 33.
37
Sum the digits in blocks of three from right to left. Since 37×27=999; round up to 1000; drop the three zeros; the multiplier is one, taking three digits at-a-time. Add these products, going from right to left. If the result is divisible by 37, then the number is divisible by 37.
Learning math on Twitter? Is this just a thought, a dream or mere wishful thinking? Not anymore!
LazyMaths.com has been sharing Free Speed Math shortcuts with its Twitter followers since the beginning of this year. Yes, One Free Shortcut a Day. Could it get better than this?
This has been so popular with our followers that they have been wanting for more! So, we plan to now offer something else for free too! More Math on Twitter!!
Starting June 15, we plan to offer one free Smart Math technique for our Twitter followers. If you are taking the GMAT, GRE, SAT, CAT, CET or any multiple choice based Math tests, this is an absolute must for you. All Smart Math techniques are in the Don’t Solve section of LazyMaths. The techniques are based on concepts of approximation, elimination and reverse substitution. Not only does using these techniques, save a ton of time to get to the answer, but it also helps in avoiding silly mistakes.
The Don’t Solve section contains problems in areas of Algebra, Percentages, Average, Ratio Proportion, Time, Speed & Distance, etc. Check out free samples here.
Eager to learn a new kind of Math right now? Go ahead, sign up with LazyMaths.com and select your choice of membership. We guarantee that you would not regret.
While we publish free speed math shortcuts and free smart math techniques, we also publish math puzzles, downloadable math learning resources like Number classification. All of these are available to our Twitter followers as well as on our blog – Zzzlog.
In short, learn math the web 2.0 way – right on Twitter! Simply follow LazyMaths on Twitter and become a pro in Twitter Math!!
Welcome to LazyMaths Blog -
The official home of the Fastest and Smartest Math around!
Check us out for some snappy Math ideas and witty Math quiz as you learn Math the intelligently lazy way!
We are the first and only website offering Speed Math shortcuts and Smart Math techniques.
Whether you are a School student taking a math test or the SAT or someone taking a competitive Math exam like GMAT, GRE or even the Math Olympiad, LazyMaths will boost your Math score and confidence.
Our students have reported getting 100% marks in their Math tests using our shortcuts and techniques!
.
(
) = 12
= 1
3m + 6w = 1/4
and w = 
47. Thus option ‘e’ is eliminated as sum of 10 + 20 + 18 = 48.
means 
; find the value of 3.124*1.39.
