whole numbers -ex 2.1 (post 2)

Good morning boys
1. In this lesson we will learn to add, subtract multiply and             divide on a number line. 

2. learn to compare and apply the above in the sums given below.


This is a number line for whole numbers.

On the number line you will see 7 is on the right of 4.
This means that the number 7 is greater than 4 

                                  7 > 4


[Note: If you keep going to the right of the number line the value of the number increases.]


Let us learn to add whole numbers on a number line.

Let us learn to subtract whole numbers on a number line 

Start from 0

go to 4, since 2 is subtracted from 4 take 2 jumps left.

You will reach 4.

Multiplication on the number line.

4 x 3 = 12 

[Note: Start from 0 move 3 units at a time to the right, make 4 moves, you will reach 12.]

Let us learn division on the number line:

[Note: Here we start from 0 go to 12 and then move to the left by jumping 3 units each]

Now lets look at Ex 2.1 Q7 

Q7. In each of the following pairs of numbers, state which whole number is on the left of the other number on the number line. Also write with the appropriate sign (>,<) between them.
a. 530, 503   b. 370, 307   c. 98765, 56789    d. 9830415, 10023001

Answer: 
a. 530 ____ 503
On the number line 530 is on the right of 503 so 530 > 503
  
    l,  th   o             cr  l  th    o 
d. 98,30,415 ____ 1,00,23,001 
1 Crore is greater that 98 lakhs so 10023001 > 9830415

You can now attempt Q7 b, c on your own.

Let do some Extra question.
a. 450, 800
b. 100, 1001
c. 88, 86
d. 712, 7120

Ex 2.1 Q8. which of the following statement are true (t) and false(f) with reasons:
Check yourself below

a. Zero is the smallest natural number: [false]
reason: 0 is a whole number

b. 400 is the predecessor of 399:[false]
reason: 400 is to the right of 399 on the number line 

c. 0 is the smallest whole number: [true]
reason: Number line starts with 0 

d. 600 is the successor of 599: [true]
reason: 600 is to the right of 599 on the number line.

e. All natural numbers are whole number: [True]
reason: natural numbers begin with 1, 2, 3..... and whole numbers with 0, 1, 2, 3..... is contained in the whole number.

f. whole numbers are natural numbers: [false]
reason: whole numbers begin with 0 and natural numbers with 1.

g. the predecessor of a 2 digit number is never a single digit number. [false]
Reason: predecessor of 10 is 9

h. 1 is the smallest whole number [false]
Reason: it is 0.

i. The natural number 1 has no predecessor [true].

j. The whole number 1 has no predecessor[false].
Reason: 0 is the predecessor

k. The whole number 13 lies between 11 and 12. [false]

l. The whole number 0 has no predecessor [true].

m. The successor of a 2 digit number is always a 2 digit number [False].
Reason: successor of 99 is 100.



Do the following Exercise based on the above:
8. Write (T) for true and (F) for false against each of the following statements:

(1) Zero is the smallest natural number.
(ii) Zero is the smallest whole number.
(iii) Every whole number is a natural number.
(iv) Every natural number is a whole number.
(v) 1 is the smallest whole number.
(vi) The natural number 1 has no predecessor.
(vii) The whole number 1 has no predecessor.
(viii) The whole number 0 has no predecessor.
(ix) The predecessor of a two-digit number is never a single-digit number.
(x) The successor of a two-digit number is always a two-digit number.
(xi) 500 is the predecessor of 499.
(xii) 7000 is the successor of 6999.


Thankyou
boys have a nice day.