[en] Samples of radio sources from the decametre - band survey obtained with the UTR-2 radio telescope are used to determine parameters of the differential number - flux density relation n(S)dS=kSsup(-γ)dS at the frequency 25 MHz through the direct count method. For flux densities 80 Jy > or approximately S > or approximately 20 Jy the parameter γ is γ₁=2.84+-0.08. This value is in good agreement with similar estimates obtained for higher frequencies. The number of sources with flux densities S>80 Jy observed at 25 MHz decreases more rapidly (γ₂>3.7) than at higher frequencies which is evidence for a strong evolution of the extended radio sources with steep spectra. It is shown that for sources with fluxes below the direct count limit (S>20 Jy) the parameters of the n(S) - relation should differ from those presented