Page 29 - Math 4

Whole Numbers Whole Numbers

h) Are all natural numbers whole numbers?

i) Are all whole numbers natural numbers?

2.3 Odd and even numbers

Let's have some discussions on these questions. In 5 pencils, four pencils
make two pairs and one
a) Does 1 pencil make a pair? pencil is left unpaired. So,
5 is an odd number!!
b) Do 2 pencils make a pair?

c) Do 3 pencils make a pair?
d) Do 4 pencils make two pairs?

In this way, 1, 3, 5, 7, ... are unpaired numbers. So, they are odd numbers.
2, 4, 6, 8, ... are paired numbers. So, they are even numbers.

Again, let's divide some of these natural numbers by 2.

2 ÷ 2 = 1 quotient and no remainder 2 is an even number.
3 ÷ 2 = 1 quotient and 1 remainder 3 is an odd number.

4 ÷ 2 = 2 quotient and no remainder 4 is an even number.
5 ÷ 2 = 2 quotient and 1 remainder 5 is an odd number.
10 ÷ 2 = 5 quotient and no remainder 10 is an even number.

17 ÷ 2 = 8 quotient and 1 remainder 17 is an odd number.

Can you investigate the idea to identify the given natural number is an odd
or an even number? Discuss with your friends.
Now, let's take some bigger numbers and see the digits at ones place of
these numbers.

71 1 is an odd number. So, 71 is an odd number.

256 6 is an even number. So, 256 is an even number.
629 9 is an odd number. So, 629 is an odd number.

540 If the digit at ones place is 0, the number is always even.
2.4 Prime and Composite numbers

Let's have some discussions on these questions.

a) Which numbers can divide 2 exactly,
2 ÷ 1 = 2 and 2 ÷ 2 = 1
or, without a remainder?
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Approved by Curriculum Development Centre, Sanothimi, Bhaktapur vedanta Excel in Mathematics - Book 4