It depends on the mode.<p>Standard will give you 49, the others 37.<p>A scientific calculator semi-officially was a floating point calculator, but the windows one had at least some capabilities beyond that, although I forgot which one exactly.<p>Perhaps the standard mode is working like a classical calculator that would also report 49 and perhaps it is just a reskin of the original one that makes everything worse, because it actually prints: 2+5*7 = 49 which does not imply calculations are done in order of input.