Important Formulas of Maths
Key Points and Useful Formulas for Exams Important Formulas For Board Exams Number system Prime numbers - A prime number is defined as a number that has no factor other than 1 and itself. Co-prime numbers - co-primes are considered in pairs and two numbers are co-prime if they have no common factors other than 1. Twin prime numbers - Twin prime numbers are the prime numbers whose difference is always equal to 2. For example, the difference between 5 and 7 is 2, and hence 5 and 7 are twin prime numbers. Composite numbers - All the natural numbers which are not prime numbers are composite numbers as they can be divided by more than two numbers. HCF and LCM About Fraction ° HCF = HCF of Numerators /LCM of Denominators ° LCM = LCM of Numerators / HCF of Denominators • Product of two Numbers = L.C.M. × H.C.F Keys/ Formulas (a + b) 2 = a 2 + 2ab + b 2 (a – b) 2 = a 2 – 2ab + b 2 (a