问题
解答题
62.8×19-8×62
1800-1350÷18×6; (2
1.9-1.9×(1.9-1.9). |
答案
(1)62.8×19-8×62
-624 5
,4 5
=62.8×19-8×62.8-62.8,
=62.8×(19-8-1),
=62.8×10,
=628;
(2)1800-1350÷18×6,
=1800-1350÷9÷2×6,
=1800-75×6,
=1800-450,
=1350;
(3)(2
+15 12
+25 8
+3.375)×7 12
,3 20
=[(2
+25 12
)+(1.625+3.375)]×7 12
,3 20
=[5+5]×
,3 20
=10×
,3 20
=1.5;
(4)1.9-1.9×(1.9-1.9),
=1.9-1.9×0,
=1.9-0,
=1.9.