The truth about the numerical value of the gibb free-energy change for a spontaneous reaction is that
gibbs free energy (delta G) negative
that is delta G<0
when the value of gibbs free energy is negative (less than zero) the reaction is spontaneous , while the value of gibbs free energy is positive ( greater than than zero) the reaction is non spontaneous, and when the gibbs free energy is equal to zero the reaction is at equilibrium.