题目内容
3.脱式计算9.43-(1.74+1.43) | 0.74×3.25+0.74×6.75 | ($\frac{5}{6}$+$\frac{7}{12}$+$\frac{3}{8}$)÷$\frac{1}{48}$ |
$\frac{5}{6}$÷(1-$\frac{9}{20}$)×$\frac{1}{5}$ | $\frac{3}{8}÷[{(\frac{1}{2}+\frac{1}{3})×\frac{3}{10}}]$ | 8÷$\frac{6}{7}$÷(2-$\frac{3}{5}$) |
分析 (1)运用减法的性质以及加法交换律与结合律简算;
(2)运用乘法分配律简算;
(3)先算括号内的,再算括号外的;
(4)先算括号内的,然后把除法变为乘法,约分计算;
(5)先算小括号内的,再算中括号内的,最后算括号外的;
(6)先算括号内的,然后约分计算.
解答 解:(1)9.43-(1.74+1.43)
=9.43-1.74-1.43
=(9.43-1.43)-1.74
=8-1.74
=6.26
(2)0.74×3.25+0.74×6.75
=0.74×(3.25+6.75)
=0.74×10
=7.4
(3)($\frac{5}{6}$+$\frac{7}{12}$+$\frac{3}{8}$)÷$\frac{1}{48}$
=$\frac{43}{24}$×48
=86
(4)$\frac{5}{6}$÷(1-$\frac{9}{20}$)×$\frac{1}{5}$
=$\frac{5}{6}$÷$\frac{11}{20}$×$\frac{1}{5}$
=$\frac{5}{6}$×$\frac{20}{11}$×$\frac{1}{5}$
=$\frac{10}{33}$
(5)$\frac{3}{8}$÷[($\frac{1}{2}$+$\frac{1}{3}$)×$\frac{3}{10}$]
=$\frac{3}{8}$÷[$\frac{5}{6}$×$\frac{3}{10}$]
=$\frac{3}{8}$÷$\frac{1}{4}$
=$\frac{3}{8}$×4
=$\frac{3}{2}$
(6)8÷$\frac{6}{7}$÷(2-$\frac{3}{5}$)
=8×$\frac{7}{6}$÷$\frac{7}{5}$
=8×$\frac{7}{6}$×$\frac{5}{7}$
=$\frac{20}{3}$
点评 考查了运算定律与简便运算,四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算顶律简便计算.