问题
解答题
计算下面各题. ①2297-156×720÷390 ②4.7×85+47×1.5 ③
④3-
|
答案
①2297-156×720÷390,
=2297-112320÷390,
=2297-288,
=2009;
②4.7×85+47×1.5,
=4.7×85+4.7×15,
=4.7×(85+15),
=4.7×100,
=470;
③
+[4 5
×(9 14
-5 6
)],4 9
=
+[4 5
×9 14
],7 18
=
+4 5
,1 4
=
;21 20
④3-
×3 2
-10 21
,2 7
=3-
-5 7
,2 7
=3-(
+5 7
),2 7
=3-1,
=2.