At the end of this post, you will learn how to use appropriate symbols(mathematical operators) for word problems such as sum,difference and product.Also, i will teach you how to solve word problems involving whole numbers and common fraction.Another method i will show you how to work on, is creating an equation from a word problem and solve them.
Base on the topics mentioned,it is very important to put your self in other to understand the above topics.A lots of people always be scared of mathematics,but few get it understood just because they always pay an attention to any topic introduce.
Now, i will begin some examples that need a serious focus,let go....
The first example to work on, is the sum and before the difference.We know that,the sum of a set of numbers is the result when the numbers are added
together.
Example 1
Let the numbers be n,n + 1, n + 2, n + 3.
n + (n + 1) + (n + 2) + (n + 3) = 58
4n + 6 = 58
subtract 6 from both sides.
4n +a 6 - 6 = 58 - 6
4n = 52
Divide both sides by 4.
4n 52
------- = -------
4 4
n = 13
The numbers are 13, 14, 15,16
we were asked to provide four consecutive numbers, and the numbers are 13, 14, 15,16.Anytime you are asked to solve this kind of math in sum,when you get your answer, start with the smallest number till n...
We also know that, the difference between two numbers is the result of subtracting one from the other.It is usual to subtract the smaller number from the larger.Therefore is set to be a positive difference.
Example 2
The difference between 8 and another number is 17.Find the two possible values for the number.
(a)Let the number be y.
assuming y > 8, then
y - 8 = 17
Add 8 to both sides
y - 8 + 8 = 17 + 8
y = 25
(b) assuming y > 8, then
8 - y =17
add y to both sides.
8 - y + y =17 + y
8 = 17 + y
subtract 17 from both sides
8 - 17 = 17 + y - 17
- 9 = y
y = -9
Wow that was a great workings,by finding the two possible value of the number. Remember, 8 = 17 + y is the same thing as y - 17 =8.In
8 = 17 + y, the 17 is facing positive area but the sign is abstract.
Example 3
The product of two or more numbers is th result when the numbers are multiplied together.
2
Find the product of -6,0.7 and 6---------
3
2
product = - 6 x 0. 7 x 6 ----------
3
7 20
= - 6 x ------ x -----
10 3
6 x 7 x 20
--------------
10 x 3
- 2 x 7 x 2
= - 28
10 to its self 1 and to 20 2 times,also 6 to its self 1 and to 6 3 times
Example 4
The product of two numbers is
4 1
8------, if one of the numbers is -------,find the other number.
9 4
Let the number be y.
1 4
-------x y = 8----
4 9
Multiply both sides by 4.
4
y =8----- x 4
9
76 x 4
= ----------
9
7
=33------
9
Example 5
What is the positive difference between 31 and the product of 4 and 14?
product of 4 and 14 = 4 x 14
= 56
Difference between 31 and 56 = 56 - 13
= 25
Notice that the problem is to find the difference between 31 and a product.Therefore find the product first (4 x 14) - 13
Is said to be an equivalent to the positive difference between 31 and the product of 4 and 14.
With the above workings,you should be able able to understand word problems.If you have questions,please put them in the comments boxes.
Class Work
Solve the following questions:
(1) Find the sum of 0.8 and 1.2
(2)The sum of three consecutive odd numbers is 80.Find the numbers
(3)Find the product 1/2 and 22
(4)Find the difference between 63 and the product of 10 and 5
(5) The product of three numbers is 0.0084.If the two numbers are 10. and 0.2,find the third number.
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