Changes

NormallyIn order for this to work properly, using <cmd>formulanumber</cmd> will we need to turn off ConTeXt's automatic formula number placement; thus the <cmd>let</cmd> command to empty <cmd>doplaceformulanumber</cmd>, and so there will which must be no interference between placed <em>after</em> the two; start of the formula. In many practical examples, however, in this case, it doesn't, and we must turn it off manually with the is not necessary; ConTeXt redefines <ttcmd>\let\doplaceformulanumber\emptydisplaylines</ttcmd> line. (The and <cmd>placeformulaeqalignno</cmd> command is still required, however, to set up the numberingdo this automatically.)  For more control over sub-formula numbering, <cmd>formulanumber</cmd> and <cmd>subformulanumber</cmd> have an optional argument parallel to that of <cmd>placeformula</cmd>, as demonstrated in this use of plain TeX's <cmd>eqalignno</cmd>, which places multiple equation numbers within one formula.