Numbers | Term 2 Chapter 2 | 2nd Maths - Comparison and formation of numbers
Chapter: 2nd Maths : Term 2 Unit 2 : Numbers
Comparison and formation of numbers
Recall
Compare the numbers
i) Colour the bigger number in each of the given pairs.
ii) Tick the smaller number in each of the given pairs.
iii) Connect the number which is equal to the given number in each of the given groups.
Learn
Biggest and smallest number
(i) Let us compare the given two-digit numbers.
Take the numbers 20, 70, 90
Here, 2 tens is less than 7 tens and 7 tens is less than 9 tens.
So, 2 tens is the smallest and 9 tens is the biggest.
20 is the smallest number and 90 is the biggest number.
(ii) Let us compare the numbers which have same digits in the tens place 25, 23, 26
Here the tens are equal. So we compare the ones. 23, 25, 26
Among 3, 5 and 6,
6 ones is the biggest and
3 ones is the smallest.
So, 26 is the biggest number and 23 is the smallest number.
(iii) Let us compare the numbers which have different digits in both the places 25, 31, 40.
Though the digits in ones place are different,
it has no significance in the comparison of numbers.
So, it is enough to compare the tens place: 25, 31, 40
4 tens is the biggest and 2 tens is the smallest.
So, 40 is the biggest number and 25 is the smallest number.
Practice
A. Circle / Underline the biggest number.
i) 34, 35, 39.
ii) 30, 80, 50.
iii) 41, 79, 19, 48.
iv) 62, 54, 76, 67.
v) 75, 57, 63, 36.
B. Box/underline the smallest number.
i) 70, 20, 10.
ii) 89, 82, 85.
iii) 35, 43, 17, 29.
iv) 59, 51, 15, 57.
v) 91, 19, 96, 69.
C. Choose the correct answer.
1. 85 is the biggest number among 60, 85, 58.
(i) 90, 74, 85
(ii) 60, 85, 58
2. Among 50, 40, 18 and 71 the smallest number is 18
(i) 18
(ii) 71
(iii) 50
(iv) 42
3. Among 62,45,75 and 52 the biggest number is 62. False
(i) True
(ii) False
Learn
Formation of two-digit numbers
Take 2 sets of number cards.
One set from 0 to 9 and the other set from 10 to 90.
Call 2 children to take one card from each set and form a two-digit number.
Formation of two-digit numbers without repetition of digits.
Let us consider the two-digit number 45. To form this number, we need to select the cards 40 and 5.
Let us consider the two-digit number 54. To form the two-digit number 54 (digits interchanged) we choose the cards 50 and 4.
Formation of two-digit numbers with repetition of digits.
Let us take the example of forming the two-digit number 66. Here we need to select the cards 60 and 6.
Ask other children to take different set of cards and to form various two-digit numbers with and without repetition of digits.
Practice
Form different two-digit numbers using the number cards given below. One is done for you.
i. Formation of two-digit numbers with repetition of digits
ii. Formation of two-digit numbers without repetition of digits
Try This
Take 2 dice and throw them. Note down the two-digit numbers (with and without repetition) formed.
For example, if the numbers seen on the face of the dice are 2 and 5, then the different ways of forming two-digit numbers are shown.
Using the given numbers, form all possible two-digit numbers and complete the table.
Pleasure Time
Complete all possible two-digit numbers (with and without repetition of digits).
6, 8 : 68, 88, 66, 86
5, 7 : 57, 75, 55, 77