问题
解答题
计算: (1)(-1.2)×(-3); (2)(-1
(3)15×(-
(4)(-1
(5)(-2.5)×2
|
答案
(1)(-1.2)×(-3)
=+(1.2×3)
=3.6;
(2)(-1
)×(-41 3
)1 2
=(-
)×(-4 3
)9 2
=
×4 3 9 2
=6;
(3)15×(-
)2 5
=-15×2 5
=-6;
(4)(-1
)×0=0;7 8
(5)(-2.5)×21 3
=-
×5 2 7 3
=-
.35 6