You find your mass to be 42 kg on a weighing machine. Is your mass more or less than 42 kg?
A weighing machine measures the weight of a body and iscalibrated to indicate mass. When we stand on a weighing machine, our weight acts downwards while upthrust due to air acts upwards. As a result, our apparent weight becomes less than the true weight. The weighing machine measures this apparent weight and hence the mass indicated by it is less than the actual mass. Our actual mass will be more than 42 kg.