Friday, 3 February 2012

Paired numbers

In this section, we will talk about Numbers and paired numbers for grade III. Numbers are fundamentals of mathematics. Numbers can be  integers (play subtracting integers worksheet here), rational, real etc.
When we talk about paired numbers it means we are talking about the patterns in them. Patterns are everywhere around us including sitting arrangement in the class. Your teacher always wants you to sit in proper arrangement in class.
By means of pattern we mean a certain rule is applied to some set of numbers and whenever we perform the reverse operation we get the numbers back and also when we apply the same operation on the result, numbers increase or decrease in same format. Improve your skills on converting of fractions to decimals
Let's take the simplest example to understand the pattern first.
1 + 2 = 3.
3 + 2 = 5
5 + 2 = 7
In the example above we apply the addition of 2. When we add 2 in 1 we gets 3 and applying the same operation (+ 2) in 3 we gets 5 same to get 7. It is clear that each number is two more than the previous. If someone ask us what would be the next number we can reply to this in no time, that the answer would be 9 (i.e. 7 + 2). We can say these numbers, that is 3, 5, 7, 9 are paired numbers.
As a grade III student you must be aware of 2's table. It also follows the pattern.
2 * 1 = 2
2 * 2 = 4
2 * 3 = 6 and so on upto
2 * 10 = 20

Now, let's discuss some real life numbers patterns. How many legs do dogs have? The answer is 4. So,
1 dog has 4 legs.
2 dogs have 8 legs (number of legs * no of dogs. That is 4 * 2)
3 dogs have 12 legs (4 * 3)

Now we have one more real life example:
Weeks and days also follow a pattern.
7 Days make a week. So,
1 week has 7 days
2 weeks have 14 days (number of weeks * 7, number of days in a week)
3 weeks have 21 days.

Now let's make those patterns bit tough.
Suppose your mom has a chart of your favorite cartoon stickers. She asked you 50 questions and for every 5 correct answers she promised you to give 3 stickers. How many stickers you get if you managed to give only 30 correct answers?
Solution: First we make a pattern for this problem.
For every 5 correct answers you get 3 stickers. For 10 correct answers you get 6. Similarly 9 stickers for 15 correct answers, and so on.

For 20 you get 12
For 25 you get 15
And for 30 you get 18.
So answer is 18 cartoon stickers for the 30 correct answers out of 50.

This is all about the paired numbers and their examples.

In upcoming posts we will discuss about Unit fractions in Grade III and Possible combinations. Visit our website for information on CBSE board physics syllabus

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