https://www.khanacademy.org/math/cc-fourth-grade-math/imp-factors-multiples-and-patterns/imp-prime-and-composite-numbers/e/prime-and-composite-numbers 2026-04-30T20:20:55.724408584Z Prime and composite numbers Practice identifying prime and composite numbers. Lindsay exercise https://www.khanacademy.org/math/class-6-ncf/x04ca845a9a148c80:prime-time/x04ca845a9a148c80:co-prime-numbers/v/co-prime-and-twin-prime-numbers 2026-01-16T09:40:42.440263577Z Co-Prime and Twin prime Numbers In this video, we explore two important concepts in number theory: co-prime numbers and twin primes. Co-prime numbers are pairs of integers that share no common factor other than 1, and we also discuss their special divisibility property—if two co-primes both divide a number, then their product also divides that number. Alongside this, we introduce twin primes, which are pairs of prime numbers differing by exactly 2, such as (11, 13) or (17, 19). With clear explanations and examples, this video makes these ideas simple to understand and shows how they reveal unique relationships between numbers. Khan Academy video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Co-Prime and Twin prime Numbers In this video, we explore two important concepts in number theory: co-prime numbers and twin primes. Co-prime numbers are pairs of integers that share no common factor other than 1, and we also discuss their special divisibility property—if two co-primes both divide a number, then their product also divides that number. Alongside this, we introduce twin primes, which are pairs of prime numbers differing by exactly 2, such as (11, 13) or (17, 19). With clear explanations and examples, this video makes these ideas simple to understand and shows how they reveal unique relationships between numbers. https://cdn.kastatic.org/ka-youtube-converted/JTqQtJYIG04.mp4/JTqQtJYIG04.mp4 269 Co-prime numbers for safekeeping treasures https://www.khanacademy.org/math/class-6-ncf/x04ca845a9a148c80:prime-time/x04ca845a9a148c80:co-prime-numbers/e/co-prime-and-twin-prime-numbers 2026-01-16T09:40:42.440263577Z Co-Prime and Twin prime Numbers In this exercise, we will learn about (a) Two numbers with only 1 as a common factor are called co-prime numbers. (b) Twin primes are prime numbers that differ from each other by two e.g. (3, 5), (5, 7) (c) A number divisible by two co-prime numbers is also divisible by their product. Khan Academy exercise https://www.khanacademy.org/math/class-6-ncf/x04ca845a9a148c80:prime-time/x04ca845a9a148c80:co-prime-numbers/e/identify-pair-of-co-prime-numbers 2025-02-25T11:20:34.857789849Z Identify co-prime numbers Identify whether a pair of numbers is co-prime or not. Aanand exercise