The How and Why of Mathematics | Hardest maths questions - refactorisation and prime numbers @THaWoM | Uploaded 5 years ago | Updated 1 hour ago
Express 8×9×10×11×12×13×14 as another product of consecutive whole numbers. How can we factorise a number without calculating it? This question from the AMC junior division was answered correctly by 0% of students! To solve it, I'll show you how composite numbers can be pulled apart into their prime factors and recombined in new ways, which is a trick I use in a lot of different situations (mental arithmetic, finding an LCM when adding fractions or doing elimination, factorising quadratics, etc.).
You can buy past AMC exam booklets at https://shop.amt.edu.au/collections/amc-resources
See the full junior playlist here: youtube.com/watch?v=QDnT4evo-5w&list=PLkNbGj38zTLMfJ7ThxPWKAzLQP6XrD1zz&index=2
I also have videos on senior AMC questions: youtube.com/watch?v=JoVB72-KSk4&list=PLkNbGj38zTLOO9aODJVznsquLhi1WeyFo&index=2
Express 8×9×10×11×12×13×14 as another product of consecutive whole numbers. How can we factorise a number without calculating it? This question from the AMC junior division was answered correctly by 0% of students! To solve it, I'll show you how composite numbers can be pulled apart into their prime factors and recombined in new ways, which is a trick I use in a lot of different situations (mental arithmetic, finding an LCM when adding fractions or doing elimination, factorising quadratics, etc.).
You can buy past AMC exam booklets at https://shop.amt.edu.au/collections/amc-resources
See the full junior playlist here: youtube.com/watch?v=QDnT4evo-5w&list=PLkNbGj38zTLMfJ7ThxPWKAzLQP6XrD1zz&index=2
I also have videos on senior AMC questions: youtube.com/watch?v=JoVB72-KSk4&list=PLkNbGj38zTLOO9aODJVznsquLhi1WeyFo&index=2
