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 shop.amt.edu.a...
See the full junior playlist here: • Hardest maths question...
I also have videos on senior AMC questions: • Hardest math questions...
26 авг 2024