js實現隨機的四則運算題目


 老師給出的題,寫一個小程序,可以生成隨機的四則運算題目給給小學生用。以前自己就寫了一個四則運算的簡單js小程序,是這樣的:

事件

這是個自己輸入的算法,但要求是自動產生隨機數。於是我用產生隨機數的函數重新寫了一個:

new document

 這樣就可以自動的生成隨機的30個四則運算題目了。但是還是有問題,小學生啊!他們不知道負數,不知道小數。所以還要加入判定條件!

switch(Arr[n]){
                case "+":{
                sum=a+b;
                break;
                }
                case "-":{
                sum=a-b;
                while(sum<0){
                    var a = GetRandomNum(1,30);
                    var b = GetRandomNum(1,30);
                    sum=a-b;
                }
                break;
                }
                case "*":{
                sum=a*b;
                break;
                }
                case "/":{
                sum=a/b;
                while(hasDot(sum)){
                        var a = GetRandomNum(1,100);
                        var b = GetRandomNum(1,100);
                        sum=a/b;
                    }
                break;
                }

這樣負數和小數都沒有了。

 不過,小學生貌似會分數的運算。於是我又開始試試寫分數的。

 <body> 
<button class="btn btn-success btn-sm" type='button' onclick="pl_f()">開始生成題目</button> <span id="text_f"></span> <script> function GetRandomNum(Min,Max) { var Range = Max - Min; var Rand = Math.random(); return(Min + Math.round(Rand * Range)); } function max_num(x,y) { var t; while (y) { t = x%y; x = y; y = t; } return x; } function fenshu(a,b,p) { if (p==1) { if (a>b) { return a+"/"+b; }else if(a<b){ return a+"/"+b; }else { return 1; } }else { var x=a/p; var y=b/p; if(y==1){ return x; }else{ return x+"/"+y; } } } function pl_f() { var son_a = GetRandomNum(1,30); var par_b = GetRandomNum(1,30); var son_c = GetRandomNum(1,30); var par_d = GetRandomNum(1,30); var X=son_a+"/"+par_b; var Y=son_c+"/"+par_d; document.write("第一個分數:"+X+"<br>"); document.write("第二個分數"+Y+"<br>"); max_x=max_num(son_a,par_b); max_y=max_num(son_c,par_d); document.write("第一個最大公約數"+max_x+"<br>"); document.write("第二個最大公約數"+max_y+"<br>"); var N=fenshu(son_a,par_b,max_x); var M=fenshu(son_c,par_d,max_y); document.write("第一個分數化簡:"+N+"<br>"); document.write("第二個分數化簡"+M); } </script> </body>

這個可以動態的生成兩個分數,然后輸出這個分數分子和分母的最大公約數。最后輸出分子的最簡式。

最后就是將分數放入整數一起了!

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
 <head>
  <title> new document </title>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
  <meta name="generator" content="editplus" />
  <meta name="author" content="" />
  <meta name="keywords" content="" />
  <meta name="description" content="" />
 </head>

 <body>
 <button type='button' onclick="play_all()">開始生成題目</button>
 <span id="text"></span>
 </body>
 <script>
  function GetRandomNum(Min,Max)
    {   
        var Range = Max - Min;   
        var Rand = Math.random();   
        return(Min + Math.round(Rand * Range));   
    }
    function max_num(x,y) {
        var t;
        while (y) {
            t = x%y;
            x = y;
            y = t;
        }
        return x;
    }
    function fenshu(a,b,p) {
        if (p==1) {
            if (a>b) {
                return a+"/"+b;
            }else if(a<b){
                return a+"/"+b;
            }else {
                return 1;
            }
        }else {
            var x=a/p;
            var y=b/p;
            if(y==1){
                return x;
            }else{
                return x+"/"+y;
            }
        }
    }
    function f_count(a,b,c,d) {
            var Arr = ["+","-","*","/"];  
            var n = GetRandomNum(0,3);
            switch(Arr[n]){
                case "+":{
                var sum_x=(a*d)+(b*c);
                var sum_y=b*d;
                max_x=max_num(sum_x,sum_y);
                max_y=max_num(sum_x,sum_y);
                var N=fenshu(sum_x,sum_y,max_x);
                return a+"/"+b+"+"+c+"/"+d+"="+N;
                break;
                }
                case "-":{
                var sum_x=(a*d)-(b*c);
                    while (sum_x<0) {
                        var a = GetRandomNum(1,30);    
                        var b = GetRandomNum(1,30);
                        var c = GetRandomNum(1,30);    
                        var d = GetRandomNum(1,30);
                        var sum_x=(a*d)-(b*c);
                    }
                var sum_y=b*d;
                max_x=max_num(sum_x,sum_y);
                max_y=max_num(sum_x,sum_y);
                var N=fenshu(sum_x,sum_y,max_x);
                return a+"/"+b+"-"+c+"/"+d+"="+N;
                break;
                }
                case "*":{
                var sum_x=a*c;
                var sum_y=b*d;
                max_x=max_num(sum_x,sum_y);
                max_y=max_num(sum_x,sum_y);
                var N=fenshu(sum_x,sum_y,max_x);
                return a+"/"+b+"*"+c+"/"+d+"="+N;
                break;
                }
                case "/":{
                var sum_x=a*d;
                var sum_y=b*c;
                max_x=max_num(sum_x,sum_y);
                max_y=max_num(sum_x,sum_y);
                var N=fenshu(sum_x,sum_y,max_x);
                return a+"/"+b+"÷"+c+"/"+d+"="+N;
                break;
                }
            }
    }
    function count(a,b){
            var Arr = ["+","-","*","/"];  
            var n = GetRandomNum(0,3);
            switch(Arr[n]){
                case "+":{
                var sum=a+b;
                return a+"+"+b+"="+sum;
                break;
                }
                case "-":{
                var sum=a-b;
                while(sum<0){
                    var a = GetRandomNum(1,30);
                    var b = GetRandomNum(1,30);
                    var sum=a-b;
                }
                return a+"-"+b+"="+sum;
                break;
                }
                case "*":{
                var sum=a*b;
                return a+"*"+b+"="+sum;
                break;
                }
                case "/":{
                var sum=a/b;
                while(a%b!==0){
                    var max_x=max_num(a,b);
                    var N=fenshu(a,b,max_x);
                    return a+"÷"+b+"="+N;
                }
                return a+"÷"+b+"="+sum;
                break;
                }
            }
    }
    function pl_f() {
        var son_a = GetRandomNum(1,30);    
        var par_b = GetRandomNum(1,30);
        var son_c = GetRandomNum(1,30);    
        var par_d = GetRandomNum(1,30);
        var suma=f_count(son_a,par_b,son_c,par_d);
        return suma;
    }
    function pl() {
            var a = GetRandomNum(1,30);   
            var b = GetRandomNum(1,30);
            var sumb=count(a,b);
            return sumb;
    }
    function play_all() {
            for (i = 1; i <=30; i++) {
                var a = GetRandomNum(0,1);
                document.getElementById("text").innerHTML+=("<br>"+"第"+i+"題:");
                switch (a) {
                    case 0:
                        var A=pl();
                        document.getElementById("text").innerHTML+=(A);
                        break;
                    case 1:
                        var B=pl_f();
                        document.getElementById("text").innerHTML+=(B);
                        break;
                }
            }
    }
 </script>
</html>

執行完節目就成這樣的啦

最后上個答案和題目分開的版本!

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
 <head>
  <title> new document </title>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
  <meta name="generator" content="editplus" />
  <meta name="author" content="" />
  <meta name="keywords" content="" />
  <meta name="description" content="" />
 </head>

 <body>
 <button type='button' onclick="play_all()">開始生成題目</button>
 <span id="text"></span>
 <span id="text2"></span>
 </body>
 <script>
  function GetRandomNum(Min,Max)
    {   
        var Range = Max - Min;   
        var Rand = Math.random();   
        return(Min + Math.round(Rand * Range));   
    }
    function max_num(x,y) {
        var t;
        while (y) {
            t = x%y;
            x = y;
            y = t;
        }
        return x;
    }
    function fenshu(a,b,p) {
        if (p==1) {
            if (a>b) {
                return a+"/"+b;
            }else if(a<b){
                return a+"/"+b;
            }else {
                return 1;
            }
        }else {
            var x=a/p;
            var y=b/p;
            if(y==1){
                return x;
            }else{
                return x+"/"+y;
            }
        }
    }
    function f_count(a,b,c,d) {
            var Arr = ["+","-","*","/"];  
            var n = GetRandomNum(0,3);
            switch(Arr[n]){
                case "+":{
                var sum_x=(a*d)+(b*c);
                var sum_y=b*d;
                max_x=max_num(sum_x,sum_y);
                max_y=max_num(sum_x,sum_y);
                var N=fenshu(sum_x,sum_y,max_x);
                return a+"/"+b+"+"+c+"/"+d+"="+N;
                break;
                }
                case "-":{
                var sum_x=(a*d)-(b*c);
                    while (sum_x<0) {
                        var a = GetRandomNum(1,30);    
                        var b = GetRandomNum(1,30);
                        var c = GetRandomNum(1,30);    
                        var d = GetRandomNum(1,30);
                        var sum_x=(a*d)-(b*c);
                    }
                var sum_y=b*d;
                max_x=max_num(sum_x,sum_y);
                max_y=max_num(sum_x,sum_y);
                var N=fenshu(sum_x,sum_y,max_x);
                return a+"/"+b+"-"+c+"/"+d+"="+N;
                break;
                }
                case "*":{
                var sum_x=a*c;
                var sum_y=b*d;
                max_x=max_num(sum_x,sum_y);
                max_y=max_num(sum_x,sum_y);
                var N=fenshu(sum_x,sum_y,max_x);
                return a+"/"+b+"*"+c+"/"+d+"="+N;
                break;
                }
                case "/":{
                var sum_x=a*d;
                var sum_y=b*c;
                max_x=max_num(sum_x,sum_y);
                max_y=max_num(sum_x,sum_y);
                var N=fenshu(sum_x,sum_y,max_x);
                return a+"/"+b+"÷"+c+"/"+d+"="+N;
                break;
                }
            }
    }
    function count(a,b){
            var Arr = ["+","-","*","/"];  
            var n = GetRandomNum(0,3);
            switch(Arr[n]){
                case "+":{
                var sum=a+b;
                return a+"+"+b+"="+sum;
                break;
                }
                case "-":{
                var sum=a-b;
                while(sum<0){
                    var a = GetRandomNum(1,30);
                    var b = GetRandomNum(1,30);
                    var sum=a-b;
                }
                return a+"-"+b+"="+sum;
                break;
                }
                case "*":{
                var sum=a*b;
                return a+"*"+b+"="+sum;
                break;
                }
                case "/":{
                var sum=a/b;
                while(a%b!==0){
                    var max_x=max_num(a,b);
                    var N=fenshu(a,b,max_x);
                    return a+"÷"+b+"="+N;
                }
                return a+"÷"+b+"="+sum;
                break;
                }
            }
    }
    function pl_f() {
        var son_a = GetRandomNum(1,30);    
        var par_b = GetRandomNum(1,30);
        var son_c = GetRandomNum(1,30);    
        var par_d = GetRandomNum(1,30);
        var suma=f_count(son_a,par_b,son_c,par_d);
        return suma;
    }
    function pl() {
            var a = GetRandomNum(1,30);   
            var b = GetRandomNum(1,30);
            var sumb=count(a,b);
            return sumb;
    }
    function play_all() {
            for (i = 1; i <=30; i++) {
                var a = GetRandomNum(0,1);
                document.getElementById("text").innerHTML+=("<br>"+"第"+i+"題:");
                switch (a) {
                    case 0:
                        var A=pl();
                        var strs = A.split("=");
                        document.getElementById("text").innerHTML+=(strs[0]+"="+"<br>");
                        document.getElementById("text2").innerHTML+=("<br>"+"第"+i+"題答案:"+strs[1]);
                        break;
                    case 1:
                        var B=pl_f();
                        var strs = B.split("=");
                        document.getElementById("text").innerHTML+=(strs[0]+"="+"<br>");
                        document.getElementById("text2").innerHTML+=("<br>"+"第"+i+"題答案:"+strs[1]);
                        break;
                }
            }
    }
 </script>
</html>

 

四則最終版


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