1.(-789целых3/5+(-101,4))+(-27,04+(-72целых24/25)) 2.(-0,16+(21/25))+(-0,875+(1/8))

1) (-789 3/5 + (-101,4)) + (-27,04 + (-72 24/25)) = -991;

    а) -789 3/5 = -(789 5 + 3)/5 = -(3945 + 3)/5 = -3948/5;

        -3948/5 + (-101,4) = -3948/5 + (-101,4) 5/5 = -3948/5 - 507/5 = -4455/5 = -891;

    б) 72 24/25 = -(72 25 + 24)/25 = -1824/25 = 1824 25 = -72,96;

       -27,04 + (-72,96) = -100.

    в) -891 + (-100) = -991.

2) (-0,16 + 21/25) + (-0,875 + 1/8) = -0,07.

    а) -0,16 25/25 + 21/25 = -4/25 + 21/25 = 17/25;

    б) -0,875 8/8 + 1/8 = -7/8 + 1/8 = -6/8;

    в) 17/25 + (-6/8) = 17 25 - 6 8 = 0,68 - 0,75 = -0,07.