Friday, April 13, 2018

CBSE board Class 6 math : Chapter 1 - Knowing numbers from unit Number System

CBSE board Class 6 math

Number System

Knowing Numbers:

Natural Numbers: Counting numbers are called as natural numbers.

Denote as N= { 1,2,3,4,5,6,7,8,9 }

1
2
3
4
5
6
7
8
9

Whole Numbers: If zero is included in the set of natural numbers known as whole numbers.

Denote as W= { 0,1,2,3,4,5,6,7,8,9 }

0
1
2
3
4
5
6
7
8
9

The numbers are written with the help of symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 knows as digits.

Expressing a number: Right to left

10x10x10x10
10x10x10
10x10
10
1
Ten Thousand
Thousand
Hundred
Ten
Ones

Example: 67138

Sixty Seven Thousand One Hundred Thirty Eight

6
7
1
3
8
Ten Thousand
Thousand
Hundred
Ten
Ones

= 6 x 10000 + 7 x 1000 + 1 x 100 + 3 x 10 + 8 x 1
= 60000 + 7000 + 100 + 30 + 8
= 67138

Comparing and Ordering:

Comparison of numbers starts from first digit of numbers from the left to right hand side.

Example 1: Compare 8534 and 8713

Number 1
Number 2
Compare

8
8
8 = 8
Compare next digit
5
7
5 < 7
Stop Comparing

Number 8713 > Number 8534

Example 2: Compare 4635 and 4619

Number 1
Number 2
Compare
Steps
4
4
4 = 4
Compare next digit
6
6
6 = 7
Compare next digit
3
1
3 > 1
Stop Comparing

Number 4635 > Number 4619

Successor and Predecessor:

Successor of number is finding by adding 1 to the number.

Successor = Number + 1

Predecessor of number is finding by subtracting by 1 to the number.

Predecessor = Number - 1

Successor = Number + 1

Periods – The Indian System of Numeration:

Periods
Crores
Lakhs
Thousands
Ones
Places
Ten Crores
Crores
Ten Lakhs
Lakhs
Ten Thousands
Thousands
Hundreds
Tens
Ones

TC
C
TL
L
T-Th
Th
H
T
O

100000000
10000000
1000000
100000
10000
1000
100
10
1
Example: A number write as 64,32,96,563

*A comma is put after first three digits then after every two digits start from right.

Example: A number 643296563 is write as 64,32,96,563

Periods – The International System of Numeration:

Periods
Billions
Millions
Thousands
Ones
Places
Hundred Billions
Ten Billions
Billions
Hundred Millions
Ten Millions
Millions
Hundred Thousands
Ten Thousands
Thousands
Hundreds
Tens
Ones

HB
TB
B
HM
TM
M
H-Th
T-Th
Th
H
T
O

100000000000
10000000000
1000000000
100000000
10000000
1000000
100000
10000
1000
100
10
1

1011
1010
109
108
107
106
105
104
103
102
101
100

*A comma is put after every three digits from the right.

Example: A number 74543231782 is write as 74,543,231,782

Note: One Trillion is 1000 billion.

Use of Numbers in daily life:

Numbers are used to measuring the length, distances, weights and amounts.
Small lengths are measured in millimeter (mm) and centimeter whereas larger lengths are measured in meter (m) and kilometer (km).

1 Meter (M) = 100 cm (centimeter) = 10000 mm (millimeter)
1 Kilometer = 1000 M x 1000 = 1000000 mm
1 Gram = 1000 mg and 1 kg (Kilogram) = 1000 gm (gram)
1 Kilogram = 1000 gm x 1000 = 1000000 mg (milligram)
1 Liter (L) = 1000 ml and 1 kL (Kiloliter) = 1000 L
1 Kiloleter = 1000 L x 1000 = 1000000 ml (milliliter)

Roman Numerals:

The Romans symbols are:

Roman Symbols
I
V
X
L
C
D
M
Meanings
1
5
10
50
100
500
1000

Example: Can be calculated as:

III = 1 + 1 +1 = 3
XXX = 10 + 10 + 10 = 30
CC = 100 + 100 = 200
CCC = 100 + 100 + 100 = 300
MM = 1000 + 1000 = 2000

Exercise:

Question 1: Write the natural numbers?

Question 2: Write the whole numbers?

Question 3: Zero is neither positive nor negative (True / False)?

Question 4: Write the number 35409 in numerals?

Question 5: Compare the number 67518 and 67499?

Question 6: Write the number 3558409 in numerals?

Question 7:  Fill in the blanks

(a) 1 Meter = _____ Centimeter
(b) 1 KM = _______Meter
(c) 1 KG = _______ gm
(d)1 KL = _______ ml

Question 8: Fill in the blanks

(a)  VI = ______
(b) XI = _______
(c) XXXVII = _______
(d)CD = _______