## 6th Class Maths:

The various topics covered in the syllabus of 6th Class Maths subject as prescribed by the NCERT is as follows:

**Knowing our numbers****Whole numbers****Playing with numbers****Basic geometrical ideas****Understanding elementary shapes****Integers****Fractions****Decimals****Data handling****Mensuration****Algebra****Ratio and proportion****Symmetry****Practical geometry**

## Knowing our numbers

This is an introduction to the number system. Students get to understand and appreciate the meaning of the words thousand, lakhs, millions etc, and are expected to know how to write big denominations of numbers and count them in this chapter in 6th class maths. They learn the Indian system of counting and the International system of counting. For example,

1 thousand = 10 hundreds

1 lakh = 100 thousands

Seventy three lakh seventy five thousand three hundred seven = 73,75,307

Twenty three lakh thirty thousand ten = 23,30,010

78,921,092 = Seventy eight million nine hundred twenty one thousand ninety two.

1.-Understanding-Number-System

## Whole numbers

This introduces students to natural, whole, non-decimal numbers. It introduces the concepts of predecessors and successors in the number system. For example:

Three natural numbers after 10999 = 11000, 11000 +1=11001, 11001+1 =11002 etc.

Predecessor of 102 = 102 – 1=101

Successor of 102 =102 + 1=103

The number 204 lies to left or right of 210? Ans: since 204 is less than 210, it lies to the left.

## Playing with numbers

This is an introduction for students to the concept of factors of numbers, multiples of numbers etc. For example

1 * 24=2 * 12=4 * 6=3 * 8 =2 * 2 * 3 * 2. Thus, 1,2,3,4,6,8,12 and 24 are factors of 24.

49=1 * 49=7 * 7 thus 1,7,49 are factors of 49.

60 = 1 * 60 = 2 * 30= 2 * 2 * 15 =4 * 15 =4 * 3 * 5 =2 * 2 * 3 * 5. Thus, 1,2,3,4,5,15,30,60 are all integers.

## Basic geometrical ideas

This introduces students to the concepts of point, line, rays, segments etc.

For example, How many lines can pass through two points? Ans – Only one.

How many lines can pass through one point? Ans – Infinite.

## Understanding elementary shapes

This is an introduction to basic shapes like circle, triangles, rectangles, squares etc.

## Integers

This chapter is about conceptualizing the number line and the positions of the numbers on the same. It enables students to have a vision about which number lies where which is more or which is less etc. This is an important chapter in 6th class maths. For example, a list of temperatures of cities on a particular day:

Siachen – 10 degrees below zero

Bhopal – 30 degree above zero

Shimla – 2 degree below zero

Delhi – 20 degree above zero

Srinagar – 5 degree below zero

Students are expected to write these in integer forms This is solved as :

Siachen = – 10^{o}

Srinagar = -5^{o}

Shimla = -2^{o}

Delhi = 20^{o}

Bhopal =30^{o}

## Fractions

This chapter introduces the concepts of fractions as parts of a whole. For example,

what fraction of a day is 6 hours? Ans = total hours of a day is 24 hours. Therefore 6/24=1/4^{th} of a day.

What fraction of an hour is 25 minutes? Ans = I hour = 60 minutes. Thus, 25/60= 5/12. Thus, 25 minutes is 5/12^{th} fraction of an hour.

## Decimals

This is an introduction to the concept of point and decimals, and their relationship to fractions. For example:

Express 1/10 as a decimal. Ans: 0.1

Express 0.007 as a fraction. Ans: 7/100

Express 85 mm in centimeter. Ans = 85 mm = 85/10 =8.5 cm

## Data handling

This shows students how to arrange numbers or items in a list according to a specified order using tally marks. It is a prerequisite to study statistics.

## Mensuration

Teaches concepts of perimeter and areas of simple geometric figures. For example, find the perimeter of a triangle of sides 10 cm, 20 cm and 15 cm. Ans: Perimeter = 10+20+15 = 45 cm.

## Ratio and proportion

Building on the previous concepts of fractions, this chapter prepares the student to see ratios and proportions as relationships of parts with respect to the whole. For example,

in a class there are 10 boys and 15 girls. What is the ratio of boys to girls, and proportion of boys to total number of students?

Ans: Ratio = 10/15 = 2/3 or 2:3. Thus for 2 boys there are 3 girls in the class. Total number of students = 10+15 =25. Thus proportion of boys = 10/25 = 2/5. Thus 2 students out of 5 students are boys which is the proportion of boys of the class.

## Algebra

This introduces students to the concepts of algebra; finding out the value of an unknown quantity using what information is known, or assessing the relationship between unknown variables using known variables. For example,

A large box of apples is emptied into 2 mall boxes, and then 5 apples are left. How many apples were in the large box? Ans: If in each box there were x apples, then in two boxes, number of apples = 2*x. Now, the number of apples left outside = 5. Therefore, total apples that originally were in the larger box = 2*x + 5

## Symmetry

This chapter builds on the conception and understanding of geometrical figures and shapes to introduce the concept of symmetry to students. Students are given incomplete figures and are expected to make them symmetric, or identify how given figures are symmetric or not, etc.

## Practical geometry

This chapter is an introduction to how to draw basic geometric shapes using the geometric equipment. Students are given specified instructions and are expected to follow the same to draw the figures. For example: – draw two circles of radii 2.5 cm and 4 cm which have a common centre. Students are expected to measure these radii on their scales and use their compasses to draw these circles to complete the exercise.