Monday, 28 November 2011

Solve fifth grade algebra using PEMDAS

Friends, today I am going to discuss about algebra solver, fifth standard mathematics topics like variables, equations etc. Students may understand how to perform basic math functions like subtraction, addition, division, decimals etc. But another possibility is that students might not know how to put all the functions together to solve a complex equation. If students start doing tasks in random manner or in improper manner then students can end up with completely incorrect results or answers. Whenever students opt to sole equations, they just remember the mnemonic device that is “ M-DAS,” which refers to Maths, Division, Addition and Subtraction. (you can also play solving equations with variables on both sides worksheet to improve your skills)

Fifth grade mathematics topics like equations, expressions etc. consists of the following parts : addition, subtraction, multiplication and division, and along with decimals and fractions. Starting from the basic what we need to do is to understand the problem and what steps required to solve a given problem. Few of the ways are:

First way is: Convert all of your decimals to fractions or convert all of your fractions to decimals, if the equation comes to solve contains a mix of both. If students want to convert fractions to decimals, what he/she needs to do is simply divide the numerator by the denominator. While converting decimals to fractions what requires is, ignore any zeros on the far right for example ignore zero in the given value 6.40. Now make a fraction with all of the numbers in the decimal over a number corresponding to the last decimal. Now the final step is to represent fraction in terms of tenths if the last value or number of the fraction is in the tenth place, this will vary according to place of the last number. For example
6.50 can be represented as 65/10 in the fraction form.

Second method: The second way is to evaluate or solve all the multiplication and division tasks. What we need to do is to mention product or quotient in place of the multiplication or division part of the equation.

Lets take an example to elaborate the above statement in the mathematical manner. In the equation
4 x 10 + 4.4 / 0.4 - 3.6 - 5,
First multiply 4 x 10 which give us 40. Then divide 4.4 by 0.4, getting 11.
After you replace "4 x 10" with "40" and "4.4 / 0.4" with "11,"
Your equation should read: 50 + 11 - 3.6 - 4.

Third way: Question is how to perform all the addition tasks. The most suitable manner is to replace the addition task with the acquired sum. Let’s take the same above example, the above formed equation can be further simplified as we all know that 50 + 11 = 61, so replace 50 + 11 with 61. Now the equation becomes 61 – 3.6 - 4

Fourth way: now the final task is to perform all subtractions. If the equation consists of more than one subtraction task, move from left to right. In the above example, first solve and perform subtraction task that is 51 – 3.6 which give us 47.4. Then subtract 4 from 47.4 , getting the final number that is 42.4.
Following the same example, first perform the subtraction task: 61 - 3.6, which equals 57.4. Then subtract 5 from 57.4, getting the final number, 52.4.

Variables are generally used to explain the general situations or real time situations and they can also be used to solve problems that in anyway would be very difficult or even impossible to solve. Whenever we are going to solve algebraic expressions or any kind of word problems, we will see the use of these applications.

Till now we have done expressions, playing with fractions, doing basic mathematical operations like addition, subtraction, multiplication and division. Now moving towards I am going to discuss about fifth grade Linear equations. In fifth grade linear functions or equations, variables are raised to power one and the equation does not contain any variable in denominator, no variables to any power other than one and no variable with under root sign.

In linear equation what we are doing is to solve the equation or getting a value of variable let’s take “x”. Solve for x means to isolate x on one side of the equation and move everything else on the other side.
X = number
Here number is the desired value which satisfies the original equation. That is when the number is substituted for the value x, the equation is true.
Let’s take an example to understand it better: in the given equation 2x + 5 = 1 we need to calculate the value for x then what we need to do is: we just need to place all the constants on one side and variables on the other side:
2x = 1 -5
2x = -4
x = -2.
Here x = -2 is the solution as we can check it in following way : 2(-2) + 5 = 1 is a true statement. For any other number, the equation or statement would be failed or results in false. For confirmation, if we mention the value of x = 3, the equation would be 2(4) + 5 = 1, which is false.
Another important thing to understand is that not every equation will have a solution. For example
x + 2 = x + 4 has no solution. It can be explained as that there is no number that can be added to two and be the same quantity as when it is added to 4. If student opt to solve for x, he/she would end up with the false statement 2 = 4.

Now I am going to discuss about how to solve an equation. In order to solve equations and to verify solutions whatever you get, first priority is that you must know the order of operations. The following order is required: Named as PEMDAS or we can say that BODMAS(B = Bracket, O = Off)

P—parentheses is the first to solve
E—exponents (and roots) are the second to perform
M—multiplication is the third
D—division third (multiplication and division should be done together, working from left to right)
A—addition is the fourth operations to be done.
S—subtraction is the fourth (addition and subtraction should be done together, working from left to right)

Another important thing is to understand the basic operations required to solve an equation. When performing with fractions you should always think of numerators and denominators as being in parentheses.
Eighth grade equations can be solved in many ways, but the general method to solve a fifth grade equation will be :
First: Both the sides of equation need to be simplified
Second: Collect all terms with variables in them on one side of the equation and all non-variable terms on the other (this is done by adding/subtracting terms).
Third: Factor out the variable.
Fourth: Finally what is required is division. Divide both the sides of the equation by the variable's coefficient.

Let’s take an example to understand it better: 2(a – 3) + 7 = 5a – 8
2a – 6 + 7 = 5a – 8
2a + 1 = 5a – 8
1 = 3a – 8
3a = 9
a = 9/3
a = 3.

Another method to solve an equation for the unknown is that we need to use inverse operations which help us to isolate the variable. These inverse operations undo all the operations that have been done to the variable. This shows that inverse operations are basically used to move quantities across the equal signs.

Let’s take an example to understand it better: In the given equation: 4x = 8
Here x is multiplied by the 4, so to move 4 across the equal sign, what we need to do is to un-multiply the 4. Therefore what is required is to divide both the sides of the equation by 4 or we can say that we can multiply each side of the equation by 1/4. In the above equation 4 + x = 8, if we want to move 4 across the equal sign or opposite side then what we need to do is to un-add 4. It can be simply stated as subtract 4 from both the sides of the equation.
In simple mathematical manner we can say that whatever we added  must be subtracted and whatever we subtract must be added. Similarly whatever we multiplied be divided and what is divided must be multiplied.

Now moving forward we all are going to learn, How can we simplify Fractions and using the Associative Property to solve Linear Equations problems. What we need to perform, find the LCD (Lowest common division) of all fractions and multiply both the sides of the equation by this number. Then, distribute this quantity on each side of the equation. In next chapter we are going to elaborate it.

In upcoming posts we will discuss about Syllabus of Grade Vth. Visit our website for information on West Bengal council of higher secondary education syllabus

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