It is not understanding, why physicists haven’t paid attention to the elementary solution of the question about the formation of inertia mass and elementary explanation of gravity force till now. As soon as velocity-addition formula has been received by Einstein, it has become clear that derivative of total velocity of one of velocities gives two summands. At that it was clear that there can be the situation, when additional speeds would be for some object with plus and with minus at once. In this case the result for two results of total velocity can be averaged and it would be possible to receive the summand of concrete figure instead of zero result which depends on the direction of varying velocity. This improvidence of scholars causes that last one hundred years scholars have been working meaninglessly but not for the development of science in this sphere.