4920÷24×20.
4
-
×1
2
+1.85+1
+7.151.4+(
-0.25)÷1
1.4×3
-1
×2
3.3×[38+3
÷(1
-0.15)].解:4920÷24×20=205×20
=4100;
-
×
=
-
×
=
-
=
;
+1.85+
+7.15=(
+
)+(1.85+7.15)=4+9
=13;
1.4+(
-0.25)÷
=1.4+0.375÷1.25
=1.4+0.3
=1.7;
1.4×
-
×
=1.4×(
-
)=1.4×1
=1.4;
3.3×[38+
÷(
÷0.15)]=3.8×[38+
÷(
×
)]=3.8×[38+
÷
]=3.8×[38+
×
]=
×
=
×
=

=
.分析:带分数乘除法要先把带分数化成假分数在计算,整数、小数、分数加减混合运算一般把分数(能化成有限小数的)化成小数计算比较简便.
点评:此题主要考查,整数、小数、分数四则混合运算的运算顺序和计算方法,及利用运算定律进行简算的能力.