http://www.edb.gov.hk/tc/curriculum-development/kla/ma/curr/pri-math-2000.html
http://www.edb.gov.hk/attachment/tc/curriculum-development/kla/ma/curr/chapter%204_4.pdf
香港教育局｜數學課程指引（小一至小六）2000
http://www.edb.gov.hk/tc/curriculum-development/kla/ma/curr/pri-math-2000.html
http://www.edb.gov.hk/attachment/tc/curriculum-development/kla/ma/curr/chapter%204_4.pdf