@vaxab23111
Первое что пришло в голову
var task = "X+2=80";
var task_temp = '';
var task_arr = [];
for (var i = 0; i < task.length; i++) {
var ch = task[i]
if (/[0-9]/i.test(ch)) {
task_temp += ch;
} else {
if (task_temp != '') {
task_arr.push(task_temp);
task_temp = '';
}
task_arr.push(ch);
}
}
if (task_temp != '') {
task_arr.push(task_temp);
}
var reversed = {
"+":"-",
"-":"+",
"*":"/",
"/":"*",
}
switch(task_arr.indexOf("X")){
case 0: {
task = task_arr[4]+reversed[task_arr[1]]+task_arr[2];
break;
}
case 2: {
task = task_arr[4]+reversed[task_arr[1]]+task_arr[0];
break;
}
case 4: {
task = task_arr.join("").replace("=X",'');
break;
}
}
eval("var result="+task)
[[A]]=Math.round(result)