This is a small work consisting of nine problems and it was originally written as part of his commentary on Chapter Nine of the Nine Chapters but later removed and made into a separate work by later editors.
Ito ay isang maliit na trabaho na binubuo ng siyam na mga problema at ito ay unang nakasulat na bilang bahagi ng kanyang kuro sa Chapter Nine ng Nine Chapters ngunit mamaya tinanggal at ginawa sa isang hiwalay na trabaho sa pamamagitan ng mamaya editor.