JSON Array values to always total up to 100% - php

Question

I have a wheel of fortune that spins, and has probability set for winning each prize that adds up to 100%. Once the quantity of a prize is met, ie, all of that prize is gone from stock, it sets the probability to 0 so you can't win it again. My problem then, is that the other values don't add up to 100. They always have to add up to 100 otherwise the wheel doesn't work.
I've got to the point of dividing all of the values by the total, rounding to two decimals and then adding them together, but i get 99 instead of 100. I've tried a few other ways of doing it and can never get to 100.
edit: My main problem seems to be that there is a 0.01% chance of winning 2 of the prizes. Dividing them by the total drops them to 0.000234234% or something similar, so when i multiply that by 100 then round that up to 2 decimals i'm getting 0.00% - but i can't think of any other way around it...
$jsonString = file_get_contents('wp-content/themes/supertheme/wheel_data.json');
$data = json_decode($jsonString, true);
echo '<pre>';
//print_r($data['segmentValuesArray'][0]['probability']);
echo '</pre>';
if ($prize1 <= 5){
$prize1before = $data['segmentValuesArray'][0]['probability'];
$data['segmentValuesArray'][0]['probability'] = 0;
}
if ($prize2 >= 5){
$data['segmentValuesArray'][1]['probability'] = 0;
}
if ($prize3 >= 300){
$data['segmentValuesArray'][2]['probability'] = 0;
}
if ($prize4 >= 500){
$data['segmentValuesArray'][3]['probability'] = 0;
}
if ($prize5 >= 10){
$data['segmentValuesArray'][4]['probability'] = 0;
}
$prize1total = $data['segmentValuesArray'][0]['probability'];
$prize2total = $data['segmentValuesArray'][1]['probability'];
$prize3total = $data['segmentValuesArray'][2]['probability'];
$prize4total = $data['segmentValuesArray'][3]['probability'];
$prize5total = $data['segmentValuesArray'][4]['probability'];
$total = $prize1total + $prize2total + $prize3total + $prize4total + $prize5total;
echo'<pre>';
print_r($total);
echo'<pre>';
$a = 0;
foreach($data['segmentValuesArray'] as $prize_array){
if($prize_array['probability'] > 0){
$a++;
}
}
$integer = $prize1before / $a;
$divided1 = $prize1total / $total;
$rounded1 = number_format((float)$divided1, 2, '.', '');
$full1 = $rounded1 * 100;
$divided2 = $prize2total / $total;
$rounded2 = number_format((float)$divided2, 2, '.', '');
$full2 = $rounded2 * 100 + $integer;
$divided3 = $prize3total / $total;
$rounded3 = number_format((float)$divided3, 2, '.', '');
$full3 = $rounded3 * 100 + $integer;
$divided4 = $prize4total / $total;
$rounded4 = number_format((float)$divided4, 2, '.', '');
$full4 = $rounded4 * 100 + $integer;
$divided5 = $prize5total / $total;
$rounded5 = number_format((float)$divided5, 2, '.', '');
$full5 = $rounded5 * 100 + $integer;
$newtotal = $full1 + $full2 + $full3 + $full4 + $full5;
echo'<pre>';
print_r($newtotal);
echo'<pre>';
$newJsonString = json_encode($data, JSON_UNESCAPED_UNICODE|JSON_UNESCAPED_SLASHES);
file_put_contents('wp-content/themes/supertheme/wheel_data.json', $newJsonString);