3 ms·
I give amc & mathcount mocks to kids every weekend & time them. There was one question everyone got under 5 seconds. I was like how did you guys do it so fast.
by dxbydt 2y ago
I give amc & mathcount mocks to kids every weekend & time them. There was one question everyone got under 5 seconds. I was like how did you guys do it so fast. Apparently aops had told them every year will have a special property that'll forsure be on the test. So that's why they all knew 45^2 was 2025.
- madcaptenor 2y agoWhen I did math competitions I remember getting the advice to know the prime factorization of the current year.
- dxbydt 2y ago45^2 = 2025 => must be the sum of first 45 odds => 1 + 3 + ... + 87+ 89 = 2025 while its not pythagorean, 40^2 + 20^2 + 5^2 = 2025. 877 is another bullcrap that has shown up on a bunch of these tests. 877 is a prime, and four times 877 is 3508 = sum of all the divisors of 2025. there's a bunch more i shared with them.