(2006?徐州)脫式計(jì)算.
24+16×11÷8 1.25×32×2.5 (2.8+3.85÷3.5)×0.2
4
7
+
1
5
-
3
7
+
4
5
10.9-(
2
5
+9.6÷4)
5
6
÷[1-(
3
4
+
1
12
)]
分析:(1)先算乘法,再算除法,最后算加法;
(2)先把32分解成4×8,再運(yùn)用乘法結(jié)合律簡算;
(3)先算小括號里面的除法,再算小括號里面的加法,最后算括號外的乘法;
(4)根據(jù)加法結(jié)合律簡算;
(5)先算小括號里面的除法,再算小括號里面的加法,最后算括號外的減法;
(6)先算小括號里面的加法,再算中括號里面的減法,最后算括號外的除法.
解答:解:(1)24+16×11÷8,
=24+176÷8,
=24+22,
=46;

(2)1.25×32×2.5,
=1.25×4×8×2.5,
=(1.25×8)×(2.5×4),
=10×10,
=100;

(3)(2.8+3.85÷3.5)×0.2,
=(2.8+1.1)×0.2,
=3.9×0.2,
=0.78;

(4)
4
7
+
1
5
-
3
7
+
4
5
,
=(
4
7
-
3
7
)+(
1
5
+
4
5
),
=
1
7
+1,
=1
1
7
;

(5)10.9-(
2
5
+9.6÷4),
=10.9-(
2
5
+2.4),
=10.9-2.8,
=8.1;

(6)
5
6
÷[1-(
3
4
+
1
12
)]
,
=
5
6
÷[1-
5
6
],
=
5
6
÷
1
6
,
=5.
點(diǎn)評:本題考查了四則混合運(yùn)算,注意運(yùn)算順序和運(yùn)算法則,靈活運(yùn)用所學(xué)的運(yùn)算定律進(jìn)行簡便計(jì)算.
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