Editing International System of Units (section)

=== 9th CGPM, the precursor to SI ===

In 1948, the 9th CGPM commissioned a study to assess the measurement needs of the scientific, technical, and educational communities and "to make recommendations for a single practical system of units of measurement, suitable for adoption by all countries adhering to the Metre Convention".<ref>{{cite web|url=http://www.bipm.org/en/CGPM/db/9/6/|title= Resolution 6 of the 9th CGPM|website=BIPM |access-date=22 August 2017 |date=1948 |url-status=dead |archive-url=https://web.archive.org/web/20170822153835/http://www.bipm.org/en/CGPM/db/9/6/ |archive-date= 22 August 2017  }}</ref> This working document was ''Practical system of units of measurement''. Based on this study, the 10th CGPM in 1954 defined an international system derived six base units: the metre, kilogram, second, ampere, degree Kelvin, and candela.

The 9th CGPM also approved the first formal recommendation for the writing of symbols in the metric system when the basis of the rules as they are now known was laid down.<ref>{{cite web |url=http://www.bipm.org/en/CGPM/db/9/7/ |title=Resolution 7 of the 9th meeting of the CGPM (1948): Writing and printing of unit symbols and of numbers |date=1948 |access-date=6 November 2012 |publisher=[[International Bureau of Weights and Measures]] |url-status=dead |archive-url=https://web.archive.org/web/20130514091113/http://www.bipm.org/en/CGPM/db/9/7/ |archive-date= May 14, 2013 }}</ref> These rules were subsequently extended and now cover unit symbols and names, prefix symbols and names, how quantity symbols should be written and used, and how the values of quantities should be expressed.<ref name="SIBrochure"/>{{rp|pages=104,130}}