Catalyzes the hydrolysis of phosphoanhydride bonds of nucleoside tri- and di-phosphates. a ribonucleoside 5'-triphosphate + 2 H2O = a ribonucleoside 5'-phosphate + 2 H(+) + 2 phosphate Highly expressed in young rosette leaves but only weakly in roots. By wounding and drought stress. No visible phenotype. Belongs to the GDA1/CD39 NTPase family.