implicit none double precision Mn,O,Al double precision MnO2,Al2O3,m_Al,n_Al double precision m_MnO2,m_Mn,m_Al2O3,left,right,check Mn=54.940000 Al=26.980000 O=15.999000 MnO2=Mn+2d0*O Al2O3=2d0*Al+3d0*O write(*,*)"give mass of Al ... : " read(*,*)m_Al n_Al=m_Al/Al m_MnO2=n_Al*3d0/4d0*MnO2 m_Mn=n_Al*3d0/4d0*Mn m_Al2O3=n_Al*1d0/2d0*Al2O3 left=m_Al+m_MnO2 right=m_Al2O3+m_Mn check=left/right write(*,*)"==============" write(*,*)"use ",m_MnO2," g of MnO2" write(*,*)"result should be: ",m_Mn," g of Mn " write(*,*)" and ",m_Al2O3," g of Al2O3" write(*,*)"left/right == ",check," << should be 1.000, check ..." end