Arf League

• Who is Cahit Arf? What is Arf League?
  

  Cahit Arf (11 October 1910 – 26 December 1997) was a Turkish mathematician. He is known for the Arf invariant of a quadratic form in characteristic 2 (applied in knot theory and surgery theory) in topology, the Hasse–Arf theorem in ramification theory, Arf semigroups, and Arf rings. For more information please check Wikipedia.
  Arf League is for enthusiasts who seeks challenging math problems. Please feel free to send your solutions or general comments to challenging-problems@ahmath.com.
• Info and Announcements

  Info

  ✔ There are 132 problems and 82 key facts, waiting for math enthusiasts!

  Dear Math Enthusiasts,

  Thanks for your interest in Arf League.
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  ✔ Please feel free to send your comments and suggestions to challenging-problems@ahmath.com and help us to promote this lovely activity by distributing the
  Arf League Poster and the QR Code.
  ✔ Arf League is looking for new problem and/or key fact writers. If you are interested in writing challenging math problems and/or key facts, please contact us. We'll be glad to meet with new question writers.

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A new problem will be released soon.

☆★☆★☆★  Newest Problem!  ★☆★☆★☆

132. Problem: A64C , proposed by Ahmet Arduc

132 is the smallest number which is the sum of all of the 2-digit numbers that can be formed with its digits.

• Correct answers have been submitted by:
  1. Caed Mark Medul Mendoza

  2. Christian Paul C. Patawaran

  3. Angelo M. Velasquez

  4. Lee Csek

  5. Lourenz Miguel Paras

  6. Sumet Ketsri

Format of the items of the selection menu: Problem Order, Problem Code (Difficulty Level). Red problems have a difficulty level of less than 0.75, thus, as an example, a 0.18 means only 18% of all answers submitted are correct.

Number of Responses: 5761
Number of Correct R.: 3973
Difficulty Level: 68.96

1. Problem: 595A , proposed by Ahmet Arduc, Tip: Key Fact(s): 7695
1 is the multiplicative identity.

Correct answers have been submitted by:

1. Mohamed Karamany

2. Jeffrey Robles

3. Joseph Rodelas

4. Mahmut Cemrek

5. Suleyman Akarsu

6. Yavuz Selim Koseoglu

7. John Gamal Aziz Attia

8. Serkan Callioglu

9. Βαρελάς Γεώρ𝛾ιος

10. Marvin Cato

11. Isaiah James de Dios Maling

12. Joselito Torculas

13. John Albert A. Reyes

14. Nheil Ignacio

15. Gerald M. Pascua

16. Angelu G. Leynes

17. Roenz Joshlee Timbol

18. Rindell Mabunga

19. Caed Mark Medul Mendoza

20. Russel J. Galanido

21. Melga Sonio

22. Mark Elis Espiridion

23. Adrian Pilotos Burgos

24. Sumet Ketsri

25. Daniel James Molina

26. Nixon Balandra

27. Jacob Sabido

28. Poetri Sonya Tarabunga

29. John Patrick

30. Lilanie Monique Torilla

31. Chris Norman Algo

32. Christian Daang

33. Grant Lewis Bulaong

34. Richard Phillip Dimaala Fernandez

35. Jake Gacuan

36. Ibrahim Demir

37. Christian Paul C. Patawaran

38. Amirul Faiz Abdul Muthalib

39. Norwyn Nicholson Kah

40. Jhepoy Dizon

41. Ralph Macarasig

42. Dan Lang

43. Chayapol

44. Dreimuru Tempest

45. Kurara Chibana

46. Lim Jing Ren

47. Alea Astrea

48. Kumar Ayush

49. Joem Canciller

50. Gluttony

51. Serdal Aslantas

52. Radu Bogo

53. Barry Villanueva

54. Randy Orton

55. Captain Magneto

56. Willie Revillame Wowowin

57. Mertkan Simsek

58. Mark Lawrence P Velasco

59. Srinivas Kanigiri

60. Prince Ivan Paraiso

61. Dale Angelo Azas Cortez

62. Mythreya Lakshman

63. Bikram Chohan

64. Law Tik Shun

65. Gideon Tomas

66. Jereco Dela Pena

67. John Aries Sarza

68. John Kenneth Vito Cruz

69. echo gabata

70. Anjelo V. Racho

71. Darwin Ojera

72. Andrei Alido

73. Sam Kashkooli

74. Mark Kenneth Dairo

75. Adisa Tolani

76. Hanelet Santos

77. Reygan Medina Dionisio

78. Angelo Velasquez

79. Marvin Cato

80. Jade N. Mijares

81. Kot Behemot

82. Lee Csek

83. Charles Dwight M. Pelaez

84. Fujiwara Toneri

85. Arcy Leann

86. Daryll Ko

87. Mark David Mortel Dela Cruz

88. Maureen Jordan

89. Zhuo Qun Song

90. Rik Smoody

91. Max Wong

92. Hanz U. Baga

93. Angelo M. Velasquez

94. angelo magdaong

95. Vaibhav Priyadarshi

96. Romeo Dane D. Melendrez

97. Bryant Ularte

98. Lisa Sauermann

99. Sajib Kumar Chowdhury

100. Raffy Salazar

101. Christian Rozano

102. Lourenz Miguel Paras

103. Ric Tura Jr

104. charles edward

105. Angelo Bungcaras Magdaong

106. Ramon Villota

107. Ian Galang

 

Futured Math Enthusiasts

The first problem
is solved firstly by
Mohamed Karamany