CLASS 6 PPT KNOWING OUR NUMBERS.ppt
- 2. INTRODUCTION Knowing our numbers helps us in counting objects in large numbers & representing them through numerals. Numbers helps in communicating through suitable number names & to count concrete objects. They help us to say which collection of bigger & arrange them in order.
- 3. PLACE VALUE CHART INDIAN Period Lakhs Thousand Ones Ten Lakhs Lakhs Ten Thousand Thousa nd Hundre ds Tens Ones T L L T Th Th H T O Place T L L T Th Th H T O 9 9 5 1 0 2 4 For example: 9951024 can be placed in place value chart as
- 4. EXAMPLE
- 7. INTERNATIONAL T M M H Th T Th Th H T O 9 6 7 4 3 6 8 2 Period Million Thousand Ones Hundred Thousan d Ten Thousan d Thousan d Hundre ds Ten s One s L T Th Th H T O Place million M Ten Millio n T M For example: 96743682 can be placed in place value chart as
- 8. CAMPARISON OF NUMBERS In order to compare two numbers, we adopt the following rulers:- RULE 1:- The number with less digits is less than the number with more digits. RULE 2:- Suppose we have to compare two numbers having the same numbers of digits than we proceed as under Step 1- First compare the digits at the leftmost place in both the numbers. Step 2- If they are equal in value then compare the second digits from the left. Step 3- if the second digits from the left are equal then compare the third digits from the left. Step 4- continue until you come across unequal digits at the corresponding places. Clearly, the number with greater such digit is the greater of the two.
- 9. SOLVED EXAMPLES Eg.1- which is greater: 24576813 or 9897686? Sol.- A number with more digits is greater so, 24576813>9897686 Eg.2- which is smaller: 1003467 or 987965? Sol.- A number with less digits is smaller so, 1003467<9897965 Eg.3- Arrange the following in ascending order: 3763214, 18340217, 984671, 3790423 Sol.- 984671<3763214<3790423<18340217 Eg.4- Arrange the following in descending order: 63872604, 4965328, 63890503, 5023145 Sol.- 63890503>63872604>5023145>4965328
- 10. A number written such that each digit has a place value according to its position in relation to other digits. Example: Write the number seven thousand, three hundred, sixty-four as a standard numeral and in expanded form. Numeral : A numeral is a symbol or name that stands for a number. Examples: 3, 49 and twelve are all numerals. So the number is an idea, the numeral is how we write it. Digit : A digit is a single symbol used to make numerals. 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 are the ten digits we use in everyday numerals. Example: The numeral 153 is made up of 3 digits ("1", "5" and "3"). Example: The numeral 46 is made up of 2 digits ("4", and "6"). Example: The numeral 9 is made up of 1 digit ("9"). So a single digit can also be a numeral . Numeral Form of Numbers
- 11. Expanded Form When we write the number 521, what that number really means is that we have the total of 500 + 20 + 1. We've expanded the number to show the value of each of its digits. When we expand a number to show the value of each digit, we're writing that number in expanded form. Expanding Brackets If we have a number, or a single algebraic term, multiplying bracketed terms, then all terms in the brackets must be multiplied as shown in the following examples. The 3 outside must multiply both terms inside the brackets. Example 3(x +2)=3x + 6.
- 12. ESTIMATION Rounding a number to the nearest ten Step 1- See the ones digit of the given number. Step 2- If ones digit is less than 5, replace ones digit by 0, & keep the other digits as they are. Step 3- If ones digit is 5, increase tens digit by 1, & replace ones digit by 0. EXAMPLE:- In 53, the ones digit is 3<5 so, the required rounded number is 50
- 13. Rounding a number to the nearest hundred Step 1- See the tens digit of the given number. Step 2- If tens digit is less than 5, replace each one of tens & ones digits by 0, & keep the other digits as they are. Step 3- If this digit is 5 or more, increase hundreds digit by 1 & replace each digit on its right by 0. EXAMPLES:- In 648, the tens digit is 4<5 So, the required rounded number is 600
- 14. Rounding a number to the nearest thousand Step 1- See the hundreds digit of the given number. Step 2- If hundreds digit is less than 5, replace each one of hundreds, tens & ones digits by 0, & keep the other digits as they are. Step 3- If hundreds digit is 5 or more, increase thousands digit by 1 & replace each digit on its right by 0. EXAMPLE:- In 5486 the hundreds digit is 4<5 So, the required rounded number is 5000
- 15. ROMAN NUMERALS One of the early systems of writing numerals is the system of roman numerals. There are seven basic symbols to write any numeral. These symbols are given below:- ROMAN NUMERAL I V X L C D M HINDU- ARABIC NUMERAL 1 5 10 50 100 500 1000 EXAMPLE:- CXIV= 100+ 10+(5-1)= 114 XL= (50-10)= 40