### CBSE Assignments class 09 Mathematics

Mathematics Assignments & Worksheets  For  Class IX Chapter-wise mathematics assignment for class 09. Important and useful extra questions strictly according to the CBSE syllabus and pattern with answer key CBSE Mathematics is a very good platform for the students and is contain the assignments for the students from 9 th  to 12 th  standard.  Here students can find very useful content which is very helpful to handle final examinations effectively.  For better understanding of the topic students should revise NCERT book with all examples and then start solving the chapter-wise assignments.  These assignments cover all the topics and are strictly according to the CBSE syllabus.  With the help of these assignments students can easily achieve the examination level and  can reach at the maximum height. Class 09 Mathematics    Assignment Case Study Based Questions Class IX

### NCERT Solution Class 9 Ch-1 Number System

Class 9 Chapter - 1 Number System
Numbers are the backbone of mathematics. Without numbers mathematics looks impossible. So students should have complete knowledge of number system. Before start this chapter students should go through some key points which are very important for accelerating the things.

 BEFORE START NCERT CHAPTER 1 CLASS IX, STUDENTS SHOULD LEARN THE FOLLOWINGS Tables (2-20),Square tables (1-30),Cubic tables (1-20)Complete number system with definitions .Different types of decimals . METHOD OF FINDING RATIONAL NUMBERS BETWEEN GIVEN TWO NUMBERS. Let two numbers are 2 and 3 These numbers can be written as 2.0 and 3.0 Rational numbers between 2 and 3 are as follows 2.1,  2.2,  2.3,  2.4,  2.5,  2.6,  2.7,  2.8,  2.9 etc. When two fractions are given then algorithm to find the rational numbers between two fractions Algorithm 1) Make the denominator of both the fractions equal by taking their LCM 2) Increase the gap between the numerators (if required) by multiplying by any larger number say 5, 10 etc. 3) Write the numbers between the numerators with the same denominator. Example Let two given numbers are :   $\frac{2}{3}$   and   $\frac{4}{5}$    LCM of 3 and 5 is = 15 Now make both the denominators equal to 15 $\frac{2}{3}\times \frac{5}{5}=\frac{10}{15}\times \frac{10}{10}=\frac{100}{150}$ $\frac{4}{5}\times \frac{3}{3}=\frac{12}{15}\times \frac{10}{10}=\frac{120}{150}$ Rational numbers between 2/3 and 4/5 $\frac{101}{150},\: \frac{102}{150},\: \frac{103}{150},\: \frac{104}{150},\: \frac{105}{150},\: \frac{106}{150}$ METHOD OF CONVERTING RATIONAL DECIMALS INTO RATIONAL NUMBER Example 1 $Let\: given\: number\: is=\: 2.\overline{4}$ $Let\: x=2.\overline{4}=2.444\: \: ....\: \: (1)$Multiplying on both side by 10 we get10x = 10 X 2.44410x = 24.444 .......... (2)From Eqn. (2) - eqn. (1)9x = 22 ⇒ x = 22/9 Example 2 $Let\: given\: number\: is=\: 2.\overline{45}$ $Let\: x=2.\overline{4}=2.454545\: \: ....\: \: (1)$ Multiplying on both side by 100 we get100x = 100 X 2.4545 ...........100x = 245.4545 .......... (2)From Eqn. (2) - eqn. (1)99x = 243 ⇒ x = 243/99 Example 3 $Let\: given\: number\: is=\: 2.\overline{456}$ $Let\: x=2.\overline{4}=2.456456\: \: ....\: \: (1)$Multiplying on both side by 1000 we get1000x = 1000 X 2.456456 ...........1000x = 2456.456456 .......... (2)From Eqn. (2) - eqn. (1)999x = 2454 ⇒ x = 2454/999 METHOD OF WRITING RATIONAL AND IRRATIONAL NUMBERS BETWEEN GIVEN TWO RATIONAL NUMBERS Algorithm 1) Write the given rational number in the decimal form upto two decimal places. 2) Write the rational numbers between the given two numbers in the decimal form. 3) Convert the given rational numbers into irrationals by placing increasing order of number of zeroes between the digits.Let given numbers are $\frac{5}{7}$   and   $\frac{9}{11}$$\frac{5}{7}$  =  0.7142 = 0.71 Approximately$\frac{9}{11}$ = 0.8181... = 0.81  ApproximatelyIrrational numbers between    $\frac{5}{7}$   and  $\frac{9}{11}$  $0.72,\: \:0.73,\: \: 0.75,\: \:0.76\: \: etc$Irrational numbers between  $\frac{5}{7}$  and  $\frac{9}{11}$$0.72072007200072\: \: .........$ $0.73073007300073\: \: .........$ $0.75075007500075\: \: .........$ $0.76076007600076\: .......etc.$