divide by 0 when all values from array is 0

If all values from an array are 0 ,will have error divide by 0...example here

array(
   array('#value' => $eu1,'#label' => t('A')), //value $eu1 is 0
   array('#value' => $eu3,'#label' => t('B')), //value $eu3 is 0
   array('#value' => $eu5,'#label' => t('C')), //value $eu5 is 0
   array('#value' => $eu7,'#label' => t('D')), //value $eu7 is 0
 ),

So , I use this before this code :

if(($eu1+$eu3+$eu5+$eu7)== 0)
{
$eunull = 1;
}
else
{
$eunull = 0;
}

An I add this line to first group of code :

array(
   array('#value' => $eu1,'#label' => t('A')), //value $eu1 is 0
   array('#value' => $eu3,'#label' => t('B')), //value $eu3 is 0
   array('#value' => $eu5,'#label' => t('C')), //value $eu5 is 0
   array('#value' => $eu7,'#label' => t('D')), //value $eu7 is 0
   array('#value' => $eunull), // in this line value for $eunull will be set to 1 if all values $eu1+$eu3+$eu5+$eu7 == 0
 ),

Scuse me for my english