分析:①把
和
分別分解為:
×2和
×6,然后把公因數(shù)提出來(lái),變?yōu)?span id="hbl1gjs" class="MathJye" mathtag="math" style="whiteSpace:nowrap;wordSpacing:normal;wordWrap:normal">
乘以三個(gè)數(shù)的和再計(jì)算較為方便;
②把算式中的分?jǐn)?shù)分別變?yōu)閮蓚(gè)數(shù)的和,然后再逐步計(jì)算即可;
③把
變?yōu)?span id="ujeegp2" class="MathJye" mathtag="math" style="whiteSpace:nowrap;wordSpacing:normal;wordWrap:normal">
×3,然后采取①的方法逐步計(jì)算較為方便;
④把算式中的后6個(gè)分?jǐn)?shù)分別變?yōu)閮蓚(gè)分?jǐn)?shù)的差,然后再逐步計(jì)算即可;
⑤先把19.3變?yōu)?6.8+2.5,計(jì)算后再把公因數(shù)提出來(lái),逐步計(jì)算即可;
⑥先把算式(1+
+
+
+
)×(
+
+
)變?yōu)椋海?+
+
+
)×(
+
+
)-
×(
+
+
).然后把公因數(shù)(1+
+
+
)提出來(lái),計(jì)算后再把公因數(shù)
提出來(lái),逐步計(jì)算即可.
解答:解:①
×
+
×
+
×
,
=
×(
+
+
),
=
×
,
=
;
②1
+
-
+
-
,
=1+
+
+
-
-
+
+
-
-
,
=2-
,
=1
;
③
×27+
×41,
=
×(27+123),
=
×150,
=30;
④
+
+
+
+
+
,
=1-
+
-
+
-
+
-
+
-
+
-
,
=1-
,
=
;
⑤6.8×16.8+19.3×3.2,
=6.8×16.8+(16.8+2.5)×3.2,
=6.8×16.8+16.8×3.2+2.5×3.2,
=16.8×﹙6.8+3.2﹚+2.5×8×0.4,
=168+8,
=176;
⑥(1+
+
+
)×(
+
+
+
)-(1+
+
+
+
)×(
+
+
),
=(1+
+
+
)×(
+
+
+
)-(1+
+
+
)×(
+
+
)-
×(
+
+
),
=(1+
+
+
)×
-
×(
+
+
),
=
×1,
=
.