Question

2.4,9.10用加减乘除运算？

每个方格代表所求的数

Answer 1

解：根据题意可得：
4÷2+9-10＝2+9-10＝1

Answer 2

32＝2×9+4+10 36＝（10-2-4）×9 48＝4×9+10+2

Answer 3

建两个实体类，一个题目实体类Subject，一个试卷类Exam。package com.exam.demo;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.function.BiFunction;

/**
* 试卷实体类
*/
public class Exam {

private List<Subject> subjectList;

public List<Subject> getSubjectList() {

return subjectList;

}

public void setSubjectList(List<Subject> subjectList) {

this.subjectList = subjectList;

}

public Exam() {

int count = 10;

List<Subject> list = new ArrayList<Subject>();

BiFunction<Integer, Integer, Integer> add = (x, y) -> x + y;

BiFunction<Integer, Integer, Integer> minus = (x, y) -> x - y;

BiFunction<Integer, Integer, Integer> multiple = (x, y) -> x * y;

BiFunction<Integer, Integer, Integer> divide = (x, y) -> x / y;

for (int i = 0; i < count; i++) {

Subject subject = new Subject();

Integer a = new Random().nextInt(99);

Integer b = new Random().nextInt(99);

subject.setA(a);

subject.setB(b);

subject.setIndex(i + 1);

Integer symbol = new Random().nextInt(3);

if (symbol == 0) {

subject.setSymbol("+");

subject.setAnswer(add.apply(a, b));

} else if (symbol == 1) {

subject.setSymbol("-");

subject.setAnswer(minus.apply(a, b));

} else if (symbol == 2) {

subject.setSymbol("×");

subject.setAnswer(multiple.apply(a, b));

} else if (symbol == 3) {

subject.setSymbol("÷");

subject.setAnswer(divide.apply(a, b));

}

list.add(subject);

}

this.subjectList = list;

}

public static void main(String[] args) {

Exam exam = new Exam();// 随机出十道题

// 查看试卷

exam.getSubjectList().forEach(subject -> {

System.out.println("第" + subject.getIndex() + "题：" + subject.getA() + " " + subject.getSymbol() + " "

+ subject.getB() + " = ? 答案：" + subject.getAnswer());

});

}

}

/**
* 定义题目的类
*
*/
class Subject {

private Integer index;

private Integer a;

private Integer b;

private String symbol;

private Integer answer;

public Integer getIndex() {

return index;

}

public void setIndex(Integer index) {

this.index = index;

}

public Integer getA() {

return a;

}

public void setA(Integer a) {

this.a = a;

}

public Integer getB() {

return b;

}

public void setB(Integer b) {

this.b = b;

}

public String getSymbol() {

return symbol;

}

public void setSymbol(String symbol) {

this.symbol = symbol;

}

public Integer getAnswer() {

return answer;

}

public void setAnswer(Integer answer) {

this.answer = answer;

}

}
运行打印结果：第1题：67 + 62 = ? 答案：129第2题：54 - 66 = ? 答案：-12第3题：15 × 36 = ? 答案：540第4题：81 + 6 = ? 答案：87第5题：87 - 70 = ? 答案：17第6题：83 - 80 = ? 答案：3第7题：1 - 88 = ? 答案：-87第8题：17 × 14 = ? 答案：238第9题：57 × 31 = ? 答案：1767第10题：73 + 6 = ? 答案：79