Subcategories

• Week 1

  Modular Arithmetic; Remainders Modulo 3 and 9; Remainders Modulo 2, 4, and 8; Another Modulus

  Day 1 Day 2 Day 3 Day 4
  23
  Topics
  75
  Posts

  S

  The reason that the greatest possible sum of A, C and E is 6 instead of 9 is because of the limitation that A+C+E=B+D. Since the greatest value B and D can be is 3, the maximum value that the sum of B+D can be is 6.

  If you set A,C, and E = 3; you'd basically say 3+3+3 = 9 = B+D, which isn't possible since the max of B+D is 6 and 9 > 6.

• Week 2

  Factors, Trailing Zeroes, GCD and LCM, Euclidean Algorithm

  Day 5 Day 6 Day 7 Day 8
  24
  Topics
  64
  Posts

  P

  Something interesting about this lesson is that this is not marked as a prerequisite. Is this a bug, or is this intentional?

• Week 3

  Repeating Patterns, Chinese Remainder Theorem, Not Relatively Prime, More Remainders

  Day 9 Day 10 Day 11 Day 12
  13
  Topics
  26
  Posts

  L

  In week 3's challenge question 19, I am not sure if this is a mistake. The answer, you say, is the number of multiples of three between 1 and 100. But if we take x=3, 3 and 0 cannot have the status of being relatively prime or not because 0 isn't defined to be (not) relatively prime to any number, according to Google searching afterward. So the answer should be 33-1, or 32. Can someone clear things up for me? Thanks a lot.

• Week 4

  Integer Equations, Powers, Divisibility by Seven, Rational Numbers

  Day 13 Day 14 Day 15 Day 16
  15
  Topics
  37
  Posts

  F

  Hi,I was reviewing everything from po shen loh daily challenge ahead of AMC10 and I'm just wondering why on the module 5 day 14 challenge part 3 on the daily challenge has a link that references this page? There's literally nothing on it! (just a quick little observation). 12b87e34-5efe-4715-b344-5d0c52dc4718-image.png