1. Write a function to calculate the sum, difference, product and quotient of two numbers. Requirements: Use the form of reference

function f1(a,b){
	console.log("and"+(a+b)+"difference"+(a-b)+"product"+(a*b)+"merchant"+(a/b));
}
f1(2,4);
f1(5,8);

2. Write a function to calculate the size of three digits and output them in order from small to large.

function f2(a,b,c){
	//Default a<b<c
	var min=a;
	if(a>b){
		a=b;
		b=min;
	}
	if(a>c){
		a=c;
		c=min;
	}
	if(b>c){
		min=b;
		b=c;
		c=min;
	}
	console.log("The order from small to large is"+a+"<"+b+"<"+c);
}
f2(3,4,1);

3. Write functions of sum, difference, product and quotient of any number

function f3(){
	var array=[1,2,3,4,5];
	var he=array[0];
	var cha=array[0];
	var ji=array[0];
	var shang=array[0];
	for(var i=1;i<5;i++){
   	 	he+=array[i];
    	cha-=array[i];
    	ji*=array[i];
    	shang/=array[i];    
	}
	console.log("Digital sum"+he+","+"The number difference is"+cha+","+"Digital product"+ji+","+"Digital quotient"+shang);
}
f3(); 

4. Write a function that generates 4-digit validation codes 10 times, and store the results in an array.

function f4(){
	var empty=[];
	for(var i=0;i<10;i++){
	    var a=Math.floor(Math.random()*10);
	    var b=Math.floor(Math.random()*10);
	    var c=Math.floor(Math.random()*10);
	    var d=Math.floor(Math.random()*10);
	     empty[i]=a.toString()+b.toString()+c.toString()+d.toString();
	}
	console.log(empty);
}
f4();

5. Write a function to calculate the odd number of any two digits. The number must be a digit. For example, to calculate the odd number of components between 0 and 3 is 01, 21, 03, 13, 23, 31.

function f5(a,b){
	var array1=[];//Number stored between a and B
	var array2=[];//Store odd numbers between a and B
	var array3=[];//Store all odd numbers
	var array4=[];//Store no equal odd numbers
	if(a>b){    //Judging the sizes of a and b
	    var tmp=a;
	    a=b;
	    b=tmp;
	}
	for(var i=a;i<=b;i++){
	    array1[array1.length]=i;
	}
	for(j=0;j<=Math.abs(b-a);j++){
	    if(array1[j]%2!==0){
	        array2[array2.length]=array1[j]
	    }
	}
	for(var k=0;k<array1.length;k++){
	    for(var m=0;m<array2.length;m++){
	        array3[array3.length]=String(array1[k])+String(array2[m]);
	        if(String(array1[k])!=String(array2[m])){
	            array4[array4.length]=String(array1[k])+String(array2[m]);
	        }
	    }
	}
	//console.log(array1);
	//console.log(array2);
	//console.log(array3);
	console.log(array4);
	}
	f5(9,0);