Exploring Number Patterns: Odd and Even Numbers | 3rd Grade Maths Term 2 Chapter 2

Patterns in numbers for odd and even numbers | 3rd Maths : Term 2 Unit 2 : Patterns

Chapter: 3rd Maths : Term 2 Unit 2 : Patterns

Patterns in numbers for odd and even numbers

Patterns in numbers for odd and even numbers and in adding odd and even numbers

Patterns in numbers for odd and even numbers and in adding odd and even numbers.

Recall

Circle the odd numbers in the given sequence.

(i) 26, 29, 37, 42, 45.

(ii) 85, 84, 75, 76, 65, 64.

(iii) 11, 22, 33, 44, 55, 66.

(iv) 357, 896, 572, 951, 865, 423.

(v) 952, 698, 342, 780, 920, 850.

Complete the table from the above numbers.

Odd number

29, 37, 45

85, 75, 65

11, 33, 55,

357, 951, 865, 423

Even number

26, 42

84, 76, 64,

22, 44, 66

896, 572,

952, 698, 342, 780, 920, 850

Observe the number chart given below. Colour the odd numbers with green and even numbers with blue.

We observe that odd and even numbers occur alternatively.

Complete the patterns :

(i) 21, 22, 23, 24, 25, 26, 27, 28.

(ii) 1, 3, 5, 7, 9, 11, 13, 15.

(iii) 2, 4, 6, 8, 10, 12, 14, 16.

(iv) 85, 86, 87, 88, 89, 90, 91, 92, 93,.

(v) 39, 41, 43, 45, 47, 49, 51, 53,.

Let’s explore patterns while adding and subtracting odd and even numbers.

Add the following numbers:

(i) 22 even + 32 even -------- 54 even --------

(ii) 73 odd + 85 odd -------- 158 even --------

(iii) 755 odd + 286 even -------- 1041 odd --------

(iv) 853 odd + 325 odd -------- 1178 even --------

(v) 978 even + 876 even -------- 1854 even --------

(vi) 252 even + 553 odd -------- 805 odd --------

Thus, we observe that addition of odd and even numbers involve a pattern.

Lets tabulate the patterns observed.

(i) Odd number + Odd number = Even number

(ii) Even number + Even number = Even number

(iii) Odd number + Even number = Odd number

(iv) Even number + Odd number = Odd number

Subtract the following numbers:

(i) 756 even − 252 even -------- 504 even --------

(ii) 895 odd − 253 odd -------- 642 even --------

(iii) 497 odd − 432 even -------- 065 odd --------

(iv) 576 even − 223 odd -------- 353 odd --------

(v) 235 odd + 521 odd -------- 756 even --------

(vi) 782 even + 141 odd -------- 923 odd --------

Let’s tabulate the patterns observed.

(i) Odd number − Odd number = Even number

(ii) Even number − Even number = Even number

(iii) Odd number − Even number = Odd number

(iv) Even number − Odd number = Odd number

Subtraction up to 99 with Regrouping | 2nd Grade Maths Term 2

Subtraction upto 99 with regrouping

2nd Maths : Term 2 Unit 2 : Numbers

Recall

i) Subtract the following two-digit numbers.

ii) Two squirrels collected nuts in the hollow of tree trunk.

Listen to their conversation.

Can you help the squirrels to find the number of nuts that are left?

Total number of nuts = 58

To find the remaining number of nuts at the end of the first day, we need to subtract 12 from 58.

Continue subtracting successively for finding the number of nuts that are left at the end of second and third day complete the subtraction procedure.

Travel Through

Each of the four friends Kavin, Kavini,Thirumagan and Sudar collected tamarind seeds and made geometrical shapes using the seeds.

Keywords: Subtract, Difference, Balance

The number of seeds used by them are tabulated as follows:

Kavin takes 22 seeds and used 9 seeds for making a triangle. How many seeds are left with him?

13 seeds left

Sudar takes 54 seeds and used 38 seeds to make a rectangle. Find the number of seeds left with her?

16 seeds left

Teacher’s Note: Teacher can motivate children to frame different subtraction questions and subtract them using the information given in the above table.

Learn: Subtract using seeds

Kavin make a triangular shape using the seeds collected by him. Observe the table, write the subtraction fact to find the number of seeds left with him.

To find the number of seeds left with Kavin, we need to subtract the number of seeds used from the number of seeds taken by him.

Let us subtract 9 from 22 using the seeds followed by the subtraction procedure. Take 22 seeds into groups of tens and ones.

Step 1: Subtract the ones

Represent 22 as 2 tens and 2 ones and cancel 9 seeds from ones.

Step 2: Regroup by converting tens to ones

We need to take away 9 seeds so we subtract the ones. We cannot subract 9 ones from 2 ones. So, we should regroup the seeds to overcome the shortage of seeds. For that 1 ten is changed into 10 ones.

Step 3: Subtract the ones

Subtract 9 ones from 12 ones.

Step 4 : Subtract the tens.

Now subtract tens. There is no tens to subtract. So 1 ten is to be written.

Hence, the number of seeds left with Kavin is 13.

Learn: Subtraction using abacus

Sudar collected 54 seeds and used 38 seeds to form a rectangle.

How many seeds are left with her?

To find the number of seeds left with Sudar we shall subract 38 from 54. We can do the subtraction 54-38 using abacus followed by the subtraction procedure. 54 has 5 tens and 4 ones.

So, put 5 green beads in tens place and 4 red beads in ones place. To take away 38 from 54 we need to take away 3 tens and 8 ones from 5 tens and 4 ones.

Step 1: Subtract ones

We cannot subtract 8 ones from 4 ones.

So exchange 1 ten as 10 ones.

So we have

Step 2: Cancel 8 ones from 14 ones

Now we can subtract 8 ones from 14 ones.

Step 3: Subtract tens

Subtract 3 tens from 4 tens.

So, the number of beads left with Sudar is 16.

Practice

1. How many more seeds were used for making rectangle than triangle ?

2. Thirumagan collected 24 seeds and used 16 seeds. How many seeds are left with him?

24 – 16 = 8

3. Kavini used 18 out of 30 seeds collected by her. What is the difference?

30−18=12

4. What is the difference in the number of seeds used by kavin and kavini?

Kavini: 18 seeds

Kavin: 9

Difference: 18 – 9 = 9

Practice

Subtract the following two-digit numbers.

32 – 28 = 4

94 – 59 = 35

72 – 46 = 26

46 – 17 = 29

50 – 36 = 14

85 – 67 = 18

Think Like a Mathematician

Write the missing numbers in the boxes below.

29 + 0 = 29

29 − 0 = 29

Try This

Find the missing digits in each of the subtraction facts.

Know more

(i) We can check the subtraction process in two ways.

Consider the subtraction fact 53 – 36=17.

(i) By adding: 36 + 17 = 53

(ii) By subtracting: 53 – 17 = 36

Given two numbers 53 and 36. When 36 is subracted from 53, we get 17. To verify the answer we can either add the number 36 and 17 to get the given number 53 or subract 17 from 53 to get the other number 36.

(ii) When we subtract 0 from any number we get the same number.

It means we did not take away anything from the number.

(iii) When a number is subtracted from itself it gives 0.

It means we have taken away completely from the given number.

Mental maths

1. Kamal fixed 56 tubelights in a party hall. If 18 tubelights were fused, then how many tubelights were used?

56 − 18 = 38 tubelight

2. A factory produced 95 cars in a day. How many cars were unsold if 37 were sold?

95 − 37 = 58 cars

3. Kumar walked 23 steps out of 90 steps to reach a shop. How many more steps he has to walk to reach the shop?

90 - 23 = 67 steps

4. Kamali had 31 rupees with her. She bought a pen for 15 rupees. She saved the remaining amount. Find the amount saved by her.

31 − 15 = 16 rupees

5. In a class of 42 students, 26 are girls. How many are boys?

42 − 26 = 16 boys

2nd Maths: Comparison and Formation of Numbers | Term 2 Unit 2

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.

Keywords: Biggest, Smallest, Bigger, Smaller

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