L4_A
More Example (combination, permutation)
L4_B
1.Flags on the masts problem
2.Permutation of “A, E, I, O, U”with blanks
3.Congress problem
Array ( [0] => Array ( [title] => L4A [link] => https://www.youtube.com/embed/sSDzCIC_oZU ) [1] => Array ( [title] => L4B [link] => https://www.youtube.com/embed/dD9YF_OCaTc ) )
Title
第1節
第2節
Syllabus
L4_A
More Example (combination, permutation)