Hi Vyatcheslav, In fact you should say \NR[+] at the end of each line in \startalign in order to get numbers. This works for me: \starttext \placeformula \startformula \startalign \NC \dot{x}(t) \NC=f(x(t), u(t)) \NR[+] \NC y(t) \NC=h(x(t), u(t)), \NR[+] \stopalign \stopformula \stoptext Best regards: OK On 31 janv. 2011, at 11:38, Vyatcheslav Yatskovsky wrote:

\starttext

% has number \placeformula \startformula f(x_0, u_0)=0. \stopformula

% has no number \placeformula \startformula \startalign \NC \dot{x}(t) \NC=f(x(t), u(t)) \NR \NC y(t) \NC=h(x(t), u(t)), \NR \stopalign \stopformula

% no numbers even here \startsubformulas \placeformula \startformula \dot{x}(t)=f(x(t), u(t)) \stopformula \placeformula \startformula y(t) =h(x(t), u(t)), \stopformula \stopsubformulas

\stoptext

Regards, Vyatcheslav

%%%%%%%%%%%%%%%%%% Otared Kavian Département de Mathématiques Université de Versailles Saint-Quentin Bâtiment Fermat 45 avenue des Etats Unis 78035 Versailles cedex Téléphone: +33 1 39 25 46 42 Secrétariat: +33 1 39 25 46 44 Secrétariat: +33 1 39 25 46 46 e-mail: Otared.Kavian@math.uvsq.fr