TS 7th Class Maths Concept
7th Class Maths Concept 7th Class Maths TS 6th Maths Concept TS 7th Maths Concept TS 8th Maths Concept TS 9th Maths Concept TS 10th Maths Concept Studying maths in VII class successfully means that children take responsibility for their learning and learn to apply the concepts to solve problems. 7th Class Maths concepts were designed by the ‘Basic in Maths’ team. These notes to do help students fall in love with mathematics and overcome fear. 1. INTEGERS Natural numbers: All the counting numbers starting from 1 are called Natural numbers. 1, 2, 3… Etc. Whole numbers: Whole numbers are the collection of natural numbers including zero. 0, 1, 2, 3 … Integers: integers are the collection of whole numbers and negative numbers. ….,-3, -2, -1, 0, 1, 2, 3,….. Integers on a number line: Operations on integers: addition of integers: 3 + 4 = 7 -2 + 4 = 2 Subtraction of integers on a number line:- 6 – 3 = 3 Multiplication of integers on a number line:- 2 × 3 ( 2 times of 3) = 6 3 × (- 4 ) ( 3 times of -4) = -12 Multiplication of two negative integers: To multiply two negative integers, first, we multiply them as whole numbers and put plus sign before the result. The multiplication of two negative integers is always negative. Ex:- -3 × -2 = 6, -10 × -2 = 20 and so on. Multiplication of more than two negative integers: • If we multiply three negative integers, then the result will be a negative integer. Ex:- -3 × -4 × -5 = -60, -1× -7 × -4 = -28 and so on. • If we multiply four negative integers, then the result will be a positive integer. Ex:- -3 × -4 × -5 × -2 = 120, -1× -7 × -4 × -2 = 56 and so on. Note:- 1. If the no. of negative integers is even, then the result will be positive. 2. If the no. of negative integers is odd, then the result will be negative. Division of integers: The division is the inverse of multiplication. When we divide a negative integer by a positive integer or a positive integer by a negative integer, we divide them as whole numbers then put negative signs for the quotient. Ex:- -3 ÷ 1 = 3, 4 ÷ -2 = -2 and so on. • When we divide a negative integer by a negative integer, we get a positive number as the quotient. Ex:- -3 ÷ -1 = 3, -4 ÷ -2 = 2 and so on. Properties of integers: 1.Closure property:- 2.commutative property:- 3.associative property:- Additive identity:- 1 + 0 = 0 + 1 = 1, 10 + 0 = 0 + 10 = 10 •For any integer ‘a’, a + 0 = 0 + a •0 is the additive identity. Additive inverse:- 2 + (-2) = (-2) + 2 = 0, 5 + (-5) = (-5) + 5 = 0 •For any integer ‘a’, a+ (-a) = (-a) + a = 0 •Additive inverse of a = -a and additive inverse of (-a) = a Multiplicative identity:- 2 × 1 = 1 × 2 = 2, 5 × 1 = 1 × 5 = 5 •For any integer ‘a’, a × 1 = 1 × a = a •1 is the multiplicative identity. multiplicative inverse:- For any integer ‘a’, 1/a × a = a × 1/a = 1 multiplicative inverse of a = 1/a Multiplicative inverse of 1/a = a. distributive property:- For any three integers a, b and c, a × (b + c) = (a × b) + (a × c). 3 × (2 + 4) = 18 (3 × 2) + (3 × 4) = 6 + 12 = 18 ∴ 3 × (2 + 4) = (3 × 2) + (3 × 4). 2. FRACTIONS, DECIMALS AND RATIONAL NUMBERS Fraction: A fraction is a number that represents a part of the whole. A group of objects is divided into equal parts, then each part is called a fraction. The proper and improper fractions: In a proper fraction, the numerator is less than the denominator. Ex: – 1/5, 2/3, and so on. In an improper fraction, the numerator is greater than the denominator. Ex: – 5/2,11/5 and so on. Comparing fractions: Like fractions: – We have to compare the like fractions with the numerator only because the like fractions have the same denominator. The fraction with the greater numerator is greater and the fraction with the smaller numerator is smaller. Ex: , and so on Unlike fractions: – With the same numerator: For comparing unlike fractions, we have to compare denominators when the numerator is the same. The fraction with a greater denominator is smaller and the fraction with a smaller denominator is smaller. Ex: – and so on. Note: – To find the equivalent fractions of both the fractions with the same denominator, we have to take the LCM of their denominators. Addition of fractions: ∗ Like Fractions: ∗ Unlike fractions: Subtraction of fractions: ∗ Like fractions: Ex: Unlike fractions: – First, we have to find the equivalent fraction of given fractions and then subtract them as like fractions Ex: Multiplication of fractions: Multiplication of fraction by a whole number: – Multiplication of numbers means adding repeatedly. Ex: – • To multiply a whole number with a proper or improper fraction, we multiply the whole number with the numerator of the fraction, keeping the denominator the same. 2.Multiplication of fraction with a fraction: – multiplication of two fractions = Division of fractions: Ex: – 2 ÷ ⇒ 6 one-thirds in two wholes Reciprocal of fraction: reciprocal of a fraction is . Note: dividing by a fraction is equal to multiplying the number by its reciprocal. For dividing a




