MATHS CLASS VI VIRTUAL LEARNING RESOURCE MATHEMATICS COURSE

MATHS CLASS VI VIRTUAL LEARNING RESOURCE

MATHEMATICS COURSE BOOK • MATHEMATICS SYLLABUS CLASS – VI (2020 -21) • PERIODIC ASSESSMENT (1) (APRIL- MAY) • Chapter 1: Knowing our Numbers • Chapter 9: Basic geometrical Ideas

KNOWING OUR NUMBERS introduction Large numbers glossary • Comparing numbers • Ordering numbers * Shifting digits *place value • Reading and writing large numbers • Indian and International system of numeration • Estimation * Roman Numerals

INTRODUCTION • Knowing our numbers helps us in counting objects in large numbers & representing them through numerals. • Numbers helps in communicating through suitable number names. • They help us to say which collection of bigger & arrange them in order.

WARM UP • In Hindu–Arabic system of numeration, we use ten symbols 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 called digits. • A group of digits denoting a number is called a numeral. • Successor of a number is 1 more than the number. • Predecessor of a number is 1 less than the number. • Face value of a digit in a number is the digit itself. • Place value of a digit in a number = Face value X Value of the place it occupies in the place value chart. • Ascending order means arrangement from the smallest to the greatest. • Descending order means arrangement from the greatest to the smallest.

PRACTICE EXERCISE • Given below are the land area of five largest countries of the world. Study the list and answer the following questions. 1. Rewrite the list in order of largest to smallest land area………………………. 2. What is the predecessor of the smallest country land area? . . 3. What is the place value of ‘ 3’ in the number giving the area of Canada? …………………. . 4. Write the successor of the largest country land area? . . . . 5. Write in expanded notation for china’s land area? . .

NATURAL NUMBERS • NATURAL NUMBERS: The numbers 1, 2, 3, 4, 5, 6, ……. . Used for counting are called counting numbers or natural numbers. Natural numbers have two main purpose: • Natural numbers can be used for counting. For example: there are 4 ice cream cones • Natural numbers can be used for ordering. For example: India is the 7 th largest country.

INTRODUCING 1, 000 • Greatest single digit number + 1 = smallest 2 -digit number 9 + 1 = 10 • Greatest 2 -digit number + 1 = smallest 3 -digit number 99 + 1 = 100 • Greatest 3 -digit number + 1 = smallest 4 -digit number 999 + 1 = 1, 000 • Greatest 4 -digit number + 1 = smallest 5 -digit number 9, 999 + 1 = 10, 000 • Greatest 5 -digit number + 1 = smallest 6 -digit number 99999 + 1 = 100000

EXAMPLE How many 4 digits numbers are there in all? Sol: The largest 4 -digit number= 9999 The smallest 4 -digit number = 1000 Number of all 4 -digit numbers = ( 9999 – 1000) + 1 = 8999 + 1 = 9000 so, there are 9000 (4 -digits) numbers in all. How many 9 digits numbers are there in all? . . How many 7 digits numbers are there in all? . .

NUMERATION AND NOTATION • NUMERAL A group of digits, denoting a number, is called a numeral. • Example: 258, 7349, 48751 , 21654, 1155478 are numerals, but mostly called numbers. • (we shall be using the words, numbers and numerals, as the same thing. ) • NUMERATION The method of expressing a number in words is called numeration. • NOTATION The method of representing a number in digits or figure is called notation.

INDIAN SYSTEM OF NUMERATION • The places in Indian Number system are grouped under the period-crores, lakhs, thousand & ones. • The ones period has 3 places –ones, tens, & hundreds & the rest have 2 each.

FEATURES OF INDIAN NUMBER SYSTEM • The period are separated by a comma while writing a number. The comma makes reading of a number system. • The digits of a number are grouped in periods starting from right to left , i. e. , from ones place to the larger places. But we read the number from left to right. • Through we mark comma when we write the number in figures , but do not put commas while writing the numbers in figures, but do not put commas while writing the number in words. • The word ‘&’is not used in the number name. • We do not use plural of the period's name when we write the number name in word.

EXAMPLE (STEP BY STEP) • Write the number ‘ five crore six lakh ten thousand nine hundred twenty-nine’ in figures. • Step 1. Make four periods as shown: C L Th O Step 2: write all the crores in the first period from the left. (We fill all the parts. For example, if it is 5 crore, we write 05) C L Th O 0 5 Step 3: write all the lakhs in the second period from the left. again fill all the parts. C L 0 5 0 Th O 6 Step 4 : write all the thousands in the third period from the left. again fill all the parts. C L 0 5 Th O 0 6 1 0 Step 5 : write all hundreds, tens and ones in the fourth period from the left. . again fill all the parts. C 0 5 L 0 Th 6 1 O 0 9 2 9

PRACTICE Can you help me to write the numeral? • Forty two lakh seventy thousand eight…………………………. . • Two crore ninety lakh fifty five thousand eight hundred……………. . . • Seven crore sixty thousand fifty five…………………………. …. • Thirteen lakh seven thousand four hundred twenty four………………. . Rewrite each of the following numbers with proper commas, using Indian place value chart: • 53684 ……………………………………………. . • 1286475…………………………………………… • 49637582……………………………………………. • 70521964…………………………………………… • 35754829…………………………………………….

Write down and solve the practice questions in the mathematics note book and hand it over to your class teacher when the school reopens. . RENU MIDHA