# Monthly Archives: September 2010

## Mental Math Multiplication

** **

** **

**Mental math multiplication** is a generally easy and enjoyable task. You need to realize that this does not require you to be a math genius; neither does it require that you memorize the entire multiplication table. In fact, this is the easiest type of mental math, as al that is required is the thought that it is simply playing around with digits. By employing simple math tricks, you will find yourself enjoying and even wanting to engage more in this exercise. This article seeks to dispel the thought that **mental math multiplication** is a** complex activity**.

Using simple tricks, you can easily multiply two digits numbers by 11. for instance if you are seeking the product of 36 and 11, the simplest way through which you can achieve the **mental math multiplication** result is by first multiplying **36 by 10**. Thereafter, add 36 to the answer. If that proves a little difficult to you, you need not panic as you can alternatively apply this other trick for any other two digits number. Start by first writing the first digit, then the addition of the first and second digit then the third one. Are you confused? Sample this.

# 36×11 =? 3(3+6)6 = 396

Do you see how simple **mental math multiplication** is? Well, you are probably wondering what happens should the sum of the first two digits add up to a number that is bigger than 9. this is in fact the simplest multiplication calculation you can ever engage in, since all you need to do is simply add 1 to the first number, then follow it up with the last digit of the addition of the two numbers before finally adding the second number. **It sounds confusing theoretically** but this is how it looks like.

# 87×11=? 8(8+7) =957

see how simple it appears?

Another of the extremely simple **mental math multiplication** tricks involves solving the square of any two digits ending with 5. You would not believe it but it is easy. For instance if you are to find the square of 25, just take the first digit and multiply it with the next higher number that is 3. Add the product to 25. This in essence means

# 25×25=? (2×3)25= 625

The same case also applies to a number such as 75. If you have followed keenly, you must have realized that these are cheap tricks. You find out that they are simplifying what would have been an otherwise difficult situation.

Those are some of the simple tricks applied in **mental math multiplication**, in a multitude of others.

## Mental Math Addition

The skills acquired through mental math calculations make it easy both for students sitting examinations and for people in other spheres of life. **Mental math addition **is one of the most basic skills in this domain and is not too difficult to learn. The strategies available differ according to levels of ability.

An example of a simple addition strategy involves the addition of several-digit numbers. The easiest way to do such sums is moving piles. It involves altering big numbers into forms we can work with. 34+56 may seem challenging but when you move 4 from the first value to the second, you have **30+60=90**. Changing the values to 10s and 5s is the best way to make it seem easy.

Another trick involves the addition of big numbers from the left side instead of from the left. This makes it rather easy to add up even four figure digits using **mental math addition. **Think about **4795+5678 as 4+5, 7+6, 9+7** and 8+5. Just note the second value of each two-digit answer and add 1 to the previous one. That means that you will first have **9363** as your answer and then add 1 to the first three values to give 10473.

When the sum involves addition of columns, it is not really necessary to write it down. Simply add up the value of one column at a time.

More taxing **mental math addition **challenges may involve adding numbers in a series. The sum of numbers in a 10-number series always comes to the value of the 7^{th} number X11. When a series comprises doubles (e.g. 2, 4, 8…), the sum of all its value is double the last figure minus the first value. In the above sequence therefore just take 8X2-2=14. The trick is especially helpful with long series containing high values.

**Addition of sequences** is another challenge that not many think can be solved mentally. If for instance you are required to add all the numbers in a sequence between 1 and 31, use this method: get the product of that final value (31) and half the next value (32/2) i.e. 31X16 and that gives you the answer. You can simplify the multiplication part of it as well and get the answer easy.

If on the other hand you are required to do a **mental math addition **of all the numbers between two numbers e.g. if you are given 5 and 19 as the values, get their sum and multiply it by half their difference +1. ([8+19=27], [19-8=11], [11+1=12], [12/2=6], [6X27=146]). That is the sum of all the numbers between 5 and 19.

## Mental Math for the Middle Grades

While most students consider mental math a tiring and difficult task, it is an important aspect of learning. **Mental math** applies in almost all areas of daily life. For this reason, it is important for them to learn the basics at an early age. It is advisable to start with simple exercises and as they age and become good at these, the equations can then be more complex demanding the need for a more thought out process. For these reasons, it is important to choose **mental math for the middle grades** that is hinges more on mind games. Children from the age of 9 to 12 should cover this though those who are a bit slow at grasping this can also be included in the program.

Since it is a bit difficult for students in this age gap to grasp the dynamics of mental math, it is advisable to start with easy strategies, which built up with time. This is regardless of whether the equations involve multiplication, addition, subtraction or division. By following a sequence, students are able to come up with the right answers until eventually; it becomes easier to solve questions that are more complex. For instance, for students to solve 64 + 77 they have to break this down to 64 +70 +7 or alternatively break it down into 60 + 70 + 11. It is important to note that this requires the student to **break down the numbers** in their heads and then mentally put them back **together**.

A percentage of students in middle grade find it hard to **calculate math mentally**. For this reason, as teachers, it is important to find ideal teaching material that will aid in exploring some of the major ways to simplify this. This is especially true if they are battling with basic math problems. However, it is ideal to provide solid facts they can fall back on when handling computing math problems mentally.

**Teachers should understand that teaching middle graders** mental maths is a step-by-step process. It should involve asking equations that involve numbers or story equations. Students should also be encouraged to answer them uniformly until eventually they are all at the same par. Also important is to ensure use of the right material to teach them. This can be easy since there are several guides on mental maths designed to cater to these needs.

## Math Tricks For Students

Maths tricks are supposed to help solve math problems without the use of a calculator. Students can use many maths tricks. We look at some few examples of different maths tricks.The most common one that students should know is that any number whose digits when added give a number that is divisible by three, should be divisible by three.

The second one is how to **multiply two digit numbers **by 11. This is so simple. Just take any number lets take an example 20, separate the two digits 2-0 and then add both digits together2+0. With the space between the two separated numbers add the total addition of both numbers220 and you have your answer.

A third example of a **maths trick for students** is when squaring any number ending in 5, they should multiply the tens digit with the next whole number and then add 25. Let us take the number 25, multiply 2 by the next whole number, which is 3. You get 6. Then add 25 to get 625, which is the correct answer.

A fourth **maths trick for students** is when multiplying two numbers whose difference is two. The trick is to square the number that is between the two and then subtract 1. Let us take an example of 8 by 10. The number between them is 9. Square it to get 81, subtract 1 to get 80.A fifth trick is when doing multiplication of decimals; students can make the sums easy by first ignoring the decimals and then adding them later. An example; 3.6 multiplied by 4. Take 36 by 4 which is equals to 144. Insert the decimal again one spot from the right to get 14.4.

Students should also learn how to calculate numbers, which are between 11 and 19 quickly. Here is a trick of how to do this. Take an example of 11 multiply it by 12. Take the larger number of the two, which is 12 and add 1 from 11, to get 13. Add a zero behind it to get 130. Then multiply 1 by 2 and add to 130 to get 132, which is the correct answer.

The last one we are going to look at is the simplest of the all. When multiplying or **dividing numbers** that end with zero(s), always drop the zeros and after doing the multiplication or the division add them back. For example, 20 multiplied by 4,000. drop the zeros and multiply 2 by 4 to get 8. Then add the zeros back to get 80000.

All these **maths tricks for students** should be regularly practiced so that the students can be able to do them quickly off head without the use of a computer. They can come in very handy especially during maths contest.

## Math Tricks for Kids

Many people refer to math as a difficult subject. However, this can be made more fun and **easy using math tricks**. These are also referred to as math strategies by some teachers. This helps the kids to be interested in the subject so that they can perform better. It also helps them to gain and practice math skills. **Kids love the tricks**, as they are a fun way to learn the subject without too much effort. Some of the tricks that can be used are:

**Math number tricks – numbers** are used in daily life. Some of the most common tricks are where you ask the child to multiply the first number of their age by 5 and add 3. After this, tell them to double the answer and finally let them add the second number of their age to the total and subtract 6. This gives the age of the person. One can also use the magic number trick where you write a 3-digit number. Get another person to write down 2 or more digits and add them up. Before you do this, write down the solution on a piece of paper and fold it. One gets the answer by taking away 2 from the last digit and placing 2 **before the number**.

Mental math trick- one can square a two-digit number that ends in 1. This is where you take away one for the number and square the answer that you get. Add this difference to the square two times. **Finally add one to the solution**. This will give you the square of the number that you were dealing with. E.g. to get square of 61

- 61-1=60.

- 60 x 60=3600.

- 3600+60+60=3720

- 1+3720 =3721 (square of 61.)

Math card tricks- these are fun tools that are **used to demonstrate various math concepts**. Children are amazed by the tools as they are amazed by the magic tricks. You can use cards for multiplication where you can pull out any card from a deck. This will help the child memorize their tables faster. **Be very careful when performing** such tricks to get all the correct answers. While children have fun when the tricks are being performed and thus will try and practice this until they master all the important concepts. They can use this in the classroom to get good grades on the subject. The math tricks for kids are also used to create shortcuts where the kids can come up with solutions to math problems fast.

## Comments