No More Carrying Over
"Carry" in Addition - Can it be Avoided?
Carrying over is a concept taught to us at a very early stage of our life. However, it has never been an easy thing to do. In adding two or more numbers, most of us face problem while “carrying over”. Larger the digits, involved in the numbers to be added, more likely it is to involve carrying. More the carrying over involved, more likely are we to make mistakes.
Friends, remember the most basic and effective rule of making arithmetic fast and quick is to break difficult calculations into simpler, easily manageable small calculations.
Any digit when added to 9 (except 0) makes carrying over mandatory. On the contrary, anything added to 0 can’t produce a two digit number. Even if 9 is added to 0, no carrying is needed.
Trick for Adding Time
Have you ever faced any problem in adding time?
If you have ever have faced the slightest difficulty in adding time or duration expressed in hours and minutes, this trick is meant for you.
Say you have to add 4 hours 55 minutes and 2 hours 40 minutes.
Make 4 hours 55 minutes into one number, which will give us 455 and do the same for the other number, 2 hours 40 minutes, giving us 240.
Shortcut Trick to Add Two Numbers
Base Method of Multiplication
Base method of multiplication derived from Vedic Mathematics can be applied for multiplication of two numbers close to 100.
This post in is in continuation of an earlier post named "Vedic Multiplication of two numbers close to hundred". Though you can understand this post stand alone, yet I'll recommend you to read the linked post before reading this one.
In this post I'll explain how to multiply two numbers lesser than the base (in this case 100). In the earlier post it was about both numbers more than 100.
Simplify Multiplication with the Lattice Method
Simplify Multiplication using Lattice Method
Multiplication tables are a pillar of growing up no matter where you are in the world. Spending most of fourth grade learning how to multiply up to 12 x 12 was a fun and exciting time, but I was never a fan of how long it took to multiply larger numbers. I didn’t learned the lattice method until later but as a fan of matrices in calculus, this alternative method of multiplication appealed to me. Here’s how it works:
Memory Tricks for Trigonometry
In the post titled Trigonometry Formula Memorization Trick, I agreed to write about a simple memory trick for memorizing the value of all major angles of different trigonometry ratios like sin30, cos45, tan60, etc. So here you go –
Values of Trigonometric Angles
Let’s start with most commonly used angles of Sin. The angles are 0°, 30° (π/6), 45° (π/4), 60° (π/3), 90° (π/2). For these angles we’ve to make fractions for which we’ve to write 0, 1, 2, 3 and 4 in the numerators and write 4 in the denominator of each fraction.
Quickly Multiply by 21
Rule for multiplying any number by 21
Start from left. Double the first digit and add it to left side neighboring digit. Repeat the steps for subsequent digits. The last number will be same as the last number of the multiplied number.
This rule is very much like the shortcut for multiplying by 11. Since 21 is sum of 11 and 10, it does belong to the same family of short cuts.
Let’s understand the whole concept with an example. Let’s multiply 5392 by 21.
The first digit of the answer will be equal to twice the first digit of 5392. To make the rule consistent assume there is a zero before the number.
Shortcut for Addition of Consecutive Numbers
In this post I’ll share with you a useful shortcut maths trick for “finding out the sum of consecutive numbers”. For example, this trick I am talking about can help you in finding the sum of all the numbers from 23 to 31 or any other set of numbers.
Shortcut Addition Trick
Add the smallest number to the largest number of the given set of consecutive numbers. Then multiply the result by the number of numbers in the set. Finally divide the result by two.
Solving the above example, let’s find: 23+24+25+26+27+28+29+30+31
Polish Hand Magic
This is a guest post by Danielle
I learned this problem from The Puzzler’s Elusion (flipkart link) by Dr. Dennis E. Shasha. It’s called Polish Hand Magic. It’s not a method of counting faster, but it is a fun little trick to show young kids (and adults) who know their multiplication tables.
In this Magical Polish tradition, a closed fist equals 5. Let’s say you want to multiply 7 x 8.
7 is represented by …||, or three fingers down and two up. 8 is represented by ..|||, or two fingers down and three up. Find the sum of the fingers that are up, in this case, the amount of vertical lines. Then multiply the number of finger down. So:
Mentally Multiply by 5, 25, 50, 250
This is a simple quicker math trick but it can be very useful for young students to solve seemingly difficult calculations. I will be glad to get your feedback on this.
Mental multiplication by 5, 25, 50, 250, 500 and so on.
Any number can be expressed in different ways. For example, 5 can be expressed as 10x(1/2).
Trick: Multiplication by 5
Step 1: Multiply the number by 10, i.e. simply place a zero after the number.
Step 2: Halve the resultant number.
Example 1:
5 × 136 = ten times of 136 i.e. 1360 should be divided by 2 = 1360/2 = 680
Example 2:
5 × 343, half of 3430 is 1715
Also check out, how to mentally multiply by 111?
How to convert from decimal to other number systems
This post will be of special interest for people who are regularly in touch with mathematics. Students preparing for competitive examinations usually have Base System (Number Systems) in the list of their topics under quantitative aptitude. You can suggest any addition to the post below by posting a comment or mailing me at vineetpatawari[at]gmail[dot]com. If you have any queries post it as comment.
Conversion from decimal to binary and other number bases
In order to convert a decimal number into its representation in a different number base, we have to be able to express the number in terms of powers of the other base. For example, if we wish to convert the decimal number 100 to base 4, we must figure out how to express 100 as the sum of powers of 4.
Who is behind QuickerMaths?
I am Vineet Patawari - PGDM (IIM Indore), ACA, B.Com(H). My passion for Mathematics, specially Vedic Maths encouraged me to start QuickerMaths
I believe that if trained properly using powerful tools like Vedic Maths, the immense intellect of human mind can be ignited instantly - find out more
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Recent Comments
watchman was paid for awaking not for sleeping so that he can see dreams.. – 05Feb12
as a night watchman he shouldnt have slept at night to get that dream... – 04Feb12
Can u plz give me clarity in ur solution Kaush sir..... – 04Feb12
thanks for these tricks. Are these from the book "quicker maths by m.tyra" ? – 03Feb12
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