(1)2.5×1.37×0.4,
=2.5×0.4×1.37,
=1×1.37,
=1.37;
(2)4.8×0.25,
=1.2×4×0.25,
=1.2×(4×0.25),
=1.2×1,
=1.2;
(3)0.89×4.8+0.89×5.2,
=0.89×(4.8+5.2),
=0.89×10,
=8.9;
(4)101×0.78,
=(100+1)×0.78,
=100×0.78+1×0.78,
=78+0.78,
=78.78;
(5)8.8×1.25,
=1.1×8×1.25,
=1.1×(8×1.25),
=1.1×10,
=11;
(6)4.3×0.8×5,
=4.3×(0.8×5),
=4.3×4,
=17.2.