Chapter: 2nd Maths : Term 3 Unit 1 : Numbers
Odd and Even numbers
Numbers that can be arranged in twos completely are called even numbers. Objects that cannot be completely arranged in twos are called odd numbers.
UNIT 1: Numbers
Travel Through
Pairs
Some of the objects that are available in pairs are given below.
Keywords: Pair, Odd, Even
Learn: Odd and Even
Let us consider two objects having same properties. For example, a set of two anklets, a set of two bangles.
Numbers that can be arranged in twos completely are called even numbers.
Here, 6 birds make 3 sets of twos. So, 6 is an even number.
Objects that cannot be completely arranged in twos are called odd numbers.
Here out of 5 birds, 2 sets of twos can be made. But 1 bird is left.
Hence 5 is an odd number.
Practice
Group the objects in twos and find whether they are even or odd. One is done for you.
Answer :
10 Even
7 Odd
8 Even
13 Odd
Learn
Let us arrange the given seeds in twos according to the number and check whether they are odd or even.
From the above table, we can conclude that the numbers 1,3,5,7,9,11,13,15,17,19 and so on have one set of seed that cannot be arranged in twos and they are called odd numbers.
The numbers 2,4,6,8,10,12,14,16,18,20 have all the seeds arranged in twos and hence they are called even numbers.
Look at the odd numbers given above. These numbers have any one of the numbers 1,3,5,7 and 9 in their one’s place.
Look at the even numbers given above. These numbers have any one of the numbers 2,4,6,8 and 0 in their one’s place.
Besides, we can observe that odd and even numbers come alternatively.
Game
* This game is played by two players using tamarind seeds. First the tamarind seeds are made into two equal groups. Let player 1 take a handful of seeds from one of the groups and player 2 guess whether the number of seeds in his hand is odd or even.
* Once player 2 gives the answer as odd or even. Player 1 arranges the seeds that are in his hands in twos to check the answer.
* If the guess made by the player 2 is right, player 1 gives all the seeds in his hand to player 2 and the chance of playing passes to player 2.
* If the guess made by the player 2 is wrong, player 2 has to give equal number of seeds to player 1 and the next chance of playing will be given to player 1.
* The game continues like this and the player with more number of seeds wins the game.
Practice
I. Circle / Underline the odd number and box / tick the even number.
(i) 71, 64 ✔, 45, 82 ✔
(ii) 9, 7, 11, 8 ✔
(iii) 10 ✔, 17, 27, 16 ✔
(iv) 94 ✔, 37, 26 ✔, 69
(v) 25, 52 ✔, 81, 18 ✔
(vi) 16 ✔, 21, 33, 30 ✔
(vii) 88 ✔, 74 ✔, 11, 53
(viii) 13, 92 ✔, 74 ✔, 66 ✔
(ix) 8 ✔, 18 ✔, 83, 86 ✔
(x) 96 ✔, 69, 72 ✔, 27
II. Write the next five even numbers.
(i) 24, 26, 28, 30, 32, 34, 36
(ii) 40, 42, 44, 46, 48, 50, 52
(iii) 88, 90, 92, 94, 96, 98, 100
(iv) 8, 10, 12, 14, 16, 18, 20
(v) 66, 68, 70, 72, 74, 76, 78
III. Write the next five odd numbers.
(i) 7, 9, 11, 13, 15, 17, 19, 21
(ii) 21, 23, 25, 27, 29, 31, 33
(iii) 83, 85, 87, 89, 91, 93, 95
(iv) 49, 51, 53, 55, 57, 59, 61
(v) 71, 73, 75, 77, 79, 81, 83
Try This
Ramya wants to form all possible two-digit numbers using only the odd numbers. Help her to form two-digit numbers using 1,3,5,7,9.
11,13,15,17,19,31,33,35,37,39,51,53,55,57,59,71,73,75,77,79,91,73,75,77,79
There are 25 number of odd two-digit numbers.
Kavitha wants to form all possible two-digit numbers using only the even numbers. Help her to form two-digit numbers using 0,2,4,6,8.
20,22,24,26,28,40,42,44,46,48,60,62,64,66,68,80,82,84,86,88
There are 20 number of even two-digit numbers.
Pleasure Time
Number chart 1-99
Observe the number chart and answer the following questions.
(i) Write all the odd numbers between 30 and 60.
31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59
(ii) Write all the even numbers between 70 and 99.
72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98
(iii) Write all the odd numbers between 1 to 40.
3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39,
(iv) Starting from 10, colour the numbers by skip counting in tens. What can you say about these numbers.
10, 20, 30, 40, 50, 60, 70, 80, 90 Even number
(v) Colour the odd numbers in the chart with blue. Observe the uncoloured numbers. What can you say about them.
Even numbers
Try This
Using the given digits, form all possible two-digit odd numbers without repetition of digits.
1) 3,6 63
2) 8,1 81
3) 5,2 25
4) 9,4 49
5) 0,7 no answer
6) 5,1 15
Among the pair of digits given above, is there any pair of number with which you cannot form two-digit odd number? Write such pair of digits. Answer: 0,7