如何在php循环创建的表单中分配变量或使用数字？

I am working on a very simple php page. The user picks how many numbers they would like to be added up, then enters the numbers on the new page, clicks a button, and then the sum is displayed.

I cannot figure out how to add up the numbers though since I can't just assign variables to each number because of the loop. I've tried this not using loops, assigning variables to each one, and simply making the button add those variables, but that required making the code for the inputs many many times, and I want this to work with a loop in case I wanted to integrate the choice to pick hundreds of numbers or something. If php isn't the best thing for this, please let me know what would be better, but anyways... how do I add up the numbers that the user inputs?

Index page:

<p>How many number would you like to add?</p>
<a href="calculator.php?inputs=2">2</a><br>
<a href="calculator.php?inputs=3">3</a><br>
<a href="calculator.php?inputs=4">4</a><br>
<a href="calculator.php?inputs=5">5</a><br>

Calculator page:

<?php

$inputs = $_GET['inputs'];

?>

<div>Enter the numbers<br>
        <?php
            for ($x=0; $x < $inputs; $x++) {
                echo '<input type="number"><br>';
            }
        ?>
</div>


<form action='' method='post'><input type='submit' value='Find value' name='findvalue'></form>

<?php 

if (isset($_POST['findvalue'])) {

}

?>

        for ($x=0; $x < $inputs; $x++) {
            echo '<input type="number"><br>';
        }

You cant use input without any name. You can use dynamic name, for example:

    for ($x=0; $x < $inputs; $x++) {
        echo '<input type="number" name="number_'.$x.'"><br>';
    }

Or better way to use array names:

    for ($x=0; $x < $inputs; $x++) {
        echo '<input type="number" name="number[]"><br>';
    }

After that, var_dump your $_POST variable.

But, best way to create dynamic fields is creating one and clone it with javascript, when user want to add next value. Example with jQuery:

<div class="myInputs"><input type="number" name="numbers[]"></div>
<a href="#" id="Add">Add input</a>
<script>
$('#Add').click(function(){
    $('.myInputs input:first').clone().appendTo(".myInputs");
    return false;
});

There is currently no JavaScript on your page. To interact with the client, JavaScript would be the best choice since there is no need to go to the backend to create input fields unless you need to save the number before interacting with the user

window.onload = function() {
  document.getElementById("nums").onchange = function() {
    var fields = document.getElementById("fields"),
      numberOfField = parseInt(this.value, 10),
      inputs = [];
    for (var i = 0; i < numberOfField; i++) {
      inputs.push('<input type="text" class="calcField" name="number' + i + '" />');
    }
    fields.innerHTML = inputs.length > 0 ? inputs.join("<br/>") : "";
  }
  document.getElementById("calc").onsubmit = function() {
    var total = 0,
      fields = document.querySelectorAll(".calcField");
    for (var i = 0; i < fields.length; i++) {
      var val = parseInt(fields[i].value, 10);
      total += isNaN(val) ? 0 : val;
    }
    document.getElementById("total").value=total;
    return false; // stop submission - remove to submit the form
  }
}

<p>How many numbers would you like to add?</p>
<form id="calc">
  <select id="nums">
    <option value="0">Please select</option>
    <option value="2">Two numbers</option>
    <option value="3">Three numbers</option>
    <option value="4">Four numbers</option>
  </select>
  <div id="fields"></div><hr/>
  <input type="submit" value="Find value" /> <input type="text" id="total" />
  
</form>

</div>

Try this:

<?php

$inputs = $_GET['inputs'];

?>
<form action='' method='post'>
<div>Enter the numbers<br>
        <?php
            for ($x=0; $x < $inputs; $x++) {
                echo '<input name="numbers[]" type="number"><br>';
            }
        ?>
</div>


<input type='submit' value='Find value' name='findvalue'>
</form>    

<?php 

if (isset($_POST['findvalue'])) {
   print_r($_POST["numbers"]);
}

?>

try adding a hidden field for the number of inputs then use it to loop

<?php

$inputs = $_GET['inputs'];

?>
<form action='' method='post'><input type='submit' value='Find value' name='findvalue'>

<div>Enter the numbers<br>
<input type="hidden" name="numberofinputs" value="<?php echo $inputs;?>"/>
        <?php
            for ($x=0; $x < $inputs; $x++) {
                //Please note the $x
                echo '<input type="number'.$x.'"><br>';
            }
        ?>
</div>


</form>

<?php 

if (isset($_POST['findvalue'])) {
     $numberOfinputs = $_POST['numberofinputs'];
     for($i=0; $i<numberOfinputs; $i++){
        //You can access it here
        echo $_POST['number'.$i];
     }
}

?>