解:
①2
+3
+4
+5
+6
,
=(2+
)+(3+
)+(4+
)+(5+
)+(6+
),
=(2+3+4+5+6)+(
+
+
+
+
),
=20+1
,
=21
;
②3.8÷
+60%×7.2-0.6,
=3.8×
+0.6×7.2-0.6,
=3.8×0.6+0.6×7.2-0.6,
=(3.8+7.2-1)×0.6,
=10×0.6,
=6;
③
+
+
+
,
=
×(
-
+
-
+
-
+
-
)
=
×(
-
+
-
)
=
×[(
+
)-(
+
)],
=
×(
-
),
=
×
,
=
;
④[(
-
+2.6÷26)÷(
-
)]÷9.375,
=[(
-
+0.1)÷(
-
)]÷9.375,
=[(1-
)÷(
-
)]÷9.375,
=[
÷
]÷9.375,
=
÷9.375,
=0.1.
分析:①把帶分?jǐn)?shù)拆成整數(shù)加分?jǐn)?shù)的形式,然后再根據(jù)加法交換律和結(jié)合律進(jìn)行簡(jiǎn)算即可;
②根據(jù)乘法分配律進(jìn)行簡(jiǎn)算;
③根據(jù)分?jǐn)?shù)的拆項(xiàng)進(jìn)行簡(jiǎn)算;
④閑散小括號(hào)里面的除法,再算小括號(hào)里面的減法,最后算小括號(hào)外面的除法.
點(diǎn)評(píng):四則運(yùn)算,先弄清它們的運(yùn)算順序,然后再進(jìn)一步計(jì)算即可,能簡(jiǎn)算的要簡(jiǎn)算.