2025年小学数学分数与小数混合运算能力提升模拟试卷

2025年小学数学分数与小数混合运算能力提升模拟试卷一、计算题要求：计算下列各题，正确书写解题过程。1.计算：$\frac{3}{4}+\frac{1}{2}-\frac{1}{4}$2.计算下列各题，找出正确的计算方法。（1）$\frac{2}{3}\times4+\frac{1}{2}\times3$（A）$\frac{2}{3}\times4+\frac{3}{2}\times1$（B）$\frac{2}{3}\times4+\frac{3}{2}\times3$（C）$\frac{2}{3}\times4+\frac{1}{2}\times3$（2）$\frac{5}{6}\div\frac{1}{3}+\frac{2}{5}\times\frac{3}{2}$（A）$\frac{5}{6}\div\frac{1}{3}+\frac{2}{5}\times\frac{3}{2}$（B）$\frac{5}{6}\times\frac{3}{1}+\frac{2}{5}\times\frac{3}{2}$（C）$\frac{5}{6}\div\frac{1}{3}+\frac{2}{5}\times\frac{3}{1}$3.计算下列各题，能简算的要简算。（1）$\frac{7}{12}+\frac{1}{4}-\frac{1}{3}$（2）$\frac{3}{5}\times\frac{4}{7}+\frac{5}{6}\times\frac{3}{4}-\frac{1}{2}\times\frac{2}{3}$4.计算下列各题，找出正确的计算方法。（1）$\frac{2}{3}\div\left(\frac{3}{4}-\frac{1}{2}\right)$（A）$\frac{2}{3}\div\left(\frac{3}{4}-\frac{1}{2}\right)$（B）$\frac{2}{3}\div\left(\frac{3}{4}+\frac{1}{2}\right)$（C）$\frac{2}{3}\div\left(\frac{3}{4}\times\frac{1}{2}\right)$（2）$\frac{1}{2}\times\left(\frac{3}{4}+\frac{1}{3}\right)-\frac{1}{3}\times\left(\frac{2}{3}+\frac{1}{4}\right)$（A）$\frac{1}{2}\times\left(\frac{3}{4}+\frac{1}{3}\right)-\frac{1}{3}\times\left(\frac{2}{3}+\frac{1}{4}\right)$（B）$\frac{1}{2}\times\left(\frac{3}{4}+\frac{1}{3}\right)+\frac{1}{3}\times\left(\frac{2}{3}+\frac{1}{4}\right)$（C）$\frac{1}{2}\times\left(\frac{3}{4}+\frac{1}{3}\right)-\frac{1}{3}\times\left(\frac{2}{3}-\frac{1}{4}\right)$二、选择题要求：选择正确的答案。1.下列哪个是分数与小数混合运算的正确顺序？（A）先乘除，后加减（B）先加减，后乘除（C）从左到右依次进行2.下列哪个是分数与小数混合运算的错误步骤？（A）先计算小数部分，再计算分数部分（B）先计算分数部分，再计算小数部分（C）同时计算分数部分和小数部分3.下列哪个是分数与小数混合运算的正确运算方法？（A）$\frac{3}{4}\times\frac{1}{2}+\frac{1}{3}\times\frac{1}{2}=\frac{1}{2}\times\left(\frac{3}{4}+\frac{1}{3}\right)$（B）$\frac{3}{4}\times\frac{1}{2}+\frac{1}{3}\times\frac{1}{2}=\frac{1}{2}\times\left(\frac{3}{4}-\frac{1}{3}\right)$（C）$\frac{3}{4}\times\frac{1}{2}+\frac{1}{3}\times\frac{1}{2}=\frac{1}{2}\times\left(\frac{3}{4}\times\frac{1}{3}\right)$4.下列哪个是分数与小数混合运算的正确计算方法？（A）$\frac{3}{4}\times\frac{1}{2}+\frac{1}{3}\times\frac{1}{2}=\frac{1}{2}\times\left(\frac{3}{4}+\frac{1}{3}\right)$（B）$\frac{3}{4}\times\frac{1}{2}+\frac{1}{3}\times\frac{1}{2}=\frac{1}{2}\times\left(\frac{3}{4}-\frac{1}{3}\right)$（C）$\frac{3}{4}\times\frac{1}{2}+\frac{1}{3}\times\frac{1}{2}=\frac{1}{2}\times\left(\frac{3}{4}\times\frac{1}{3}\right)$三、应用题要求：根据题目要求，列出算式，并计算出结果。1.小华买了一本书，书的原价是$\frac{15}{8}$元，书店打八折出售，请问小华实际支付了多少钱？2.小明有$\frac{3}{4}$袋糖，每袋糖有$\frac{1}{3}$千克，请问小明一共有多少千克糖？四、填空题要求：在横线上填入正确的数字或分数。1.$\frac{2}{5}+\frac{3}{10}=\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\本次试卷答案如下：一、计算题1.解析：先将分数相加，再相减。$\frac{3}{4}+\frac{1}{2}-\frac{1}{4}=\frac{3}{4}+\frac{2}{4}-\frac{1}{4}=\frac{5}{4}-\frac{1}{4}=\frac{4}{4}=1$2.解析：选择正确的计算方法，确保计算顺序正确。（1）正确答案是（C）$\frac{2}{3}\times4+\frac{1}{2}\times3$，因为乘法和除法的优先级高于加法和减法。（2）正确答案是（A）$\frac{5}{6}\div\frac{1}{3}+\frac{2}{5}\times\frac{3}{2}$，因为除法和乘法的优先级高于加法和减法。3.解析：能简算的要简算，确保计算效率。（1）$\frac{7}{12}+\frac{1}{4}-\frac{1}{3}=\frac{7}{12}+\frac{3}{12}-\frac{4}{12}=\frac{10}{12}-\frac{4}{12}=\frac{6}{12}=\frac{1}{2}$（2）$\frac{3}{5}\times\frac{4}{7}+\frac{5}{6}\times\frac{3}{4}-\frac{1}{2}\times\frac{2}{3}=\frac{12}{35}+\frac{15}{24}-\frac{1}{3}=\frac{12}{35}+\frac{25}{40}-\frac{20}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{6}=\frac{12}{35}+\frac{25}{40}-\frac{10}{30}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{35}+\frac{25}{40}-\frac{40}{60}=\frac{12}{35}+\frac{25}{40}-\frac{2}{3}=\frac{12}{3