Integration Class 7 Notes Maths | StudyTution

  • Representation of integers on the number line and their addition and subtraction
  • Product of a positive integer and a negative integer is a negative integer, i.e, a × (–b) = – ab, where a and b are positive integers.
  • Product of two negative integers is a positive integer, i.e., (–a) × (–b) = ab, where a and b are positive integers.
  •  Product of even number of negative integers is positive, where as the product of odd number of negative integers is negative,
  •  When a positive integer is divided by a negative integer or vice-versa and the quotient obtained is an integer  then it is a negative integer, i.e., a ÷ (–b) = (–a) ÷ b = – a b , where a and b are positive integers and – a
    b is an integer
  • When a negative integer is divided by another negative integer to give an integer then it gives a positive integer, i.e., (–a) ÷ (–b) = a b , where a and b are positive integers and a b is also an integer.
  • For any integer a, a ÷ 1 = a and a ÷ 0 is not defined.

Properties of integers:

  • Integers are closed under addition, subtraction and multiplication.
  • Addition and multiplication are commutative for integers, i.e., a + b = b + a and a × b = b × a for any two integers a and b.
  • Addition and multiplication are associative for integers, i.e., (a + b) + c = a + (b + c) and (a × b) × c = a × (b × c) for any three integers a, b and c.
  • Zero (0) is an additive identity for integers, i.e., a + 0 = 0 + a = a for any integer a.
  • 1 is multiplicative identity for integers, i.e., a × 1 = 1 × a = a for any integer a.
  • Integers show distributive property of multiplication over addition, i.e., a × (b + c) = a × b + a × c for any three  integers a, b and c.
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