A procedure for designing an approximate solution of the Crocco boundary typical problem has been proposed in the paper. The procedure calls for the change of this initial problem by a nonlinear integral equation. The latter was solved by direct calculation of the integral using the mean-value theorem. . The averaging parameter was eliminated by integrating over the parameter in the (0, 1) interval. Widening the scope of the solution procedure was demonstrated and weak solutions were found. For the classical case, the weak solution was not too different from the Blasius exact one. The approximate value of the Blasius constant turned out to be 1/3 and differed from the exact one (0.33206) by 0.3 %.