Hi is there any posibility to get this working?

{exp:cartthrob:arithmetic expression="{option_price_numeric} -({option_price_numeric} * {exp:low_variables:single var='early_bird_discount'} / 100)"}

In {exp:low_variables:single var='early_bird_discount'} is 30 in this example I'm getting an "undefined variable" error and I know this is correct but I don't know how exactly get the right result for this


Using the first option Rob Sanchez suggests gives me the following error: Unparsed EE tags in expression, check parse order. Perhaps it is important for you that the tag is nested into several tags in an embed template:

{exp:channel:entries channel="events" require_entry="yes" entry_id="{embed:entry_id}"}
  {exp:cartthrob:item_options entry_id="{entry_id}"}
    {categories show_group="24"}
        {if option_value == "{embed:option}"}

          {if category_id =="160"}
            {if "{event_early_bird_date format='%U'}" >= "{current_time format='%U'}" && "{exp:low_variables:single var='siteA:early_bird_discount'}" >"{embed:another_discount}"}
{!-- ##### --}
              {exp:cartthrob:arithmetic expression="{option_price_numeric} -({option_price_numeric} * {early_bird_discount} / 100)"}
{!-- ##### --}
              {exp:cartthrob:arithmetic expression="{option_price_numeric} -({option_price_numeric} * {embed:another_discount} / 100) + {embed:membrr_price}"}
          {if:elseif category_id =="161"}


Update 2

I figured out the problem I think. early_bird_discount is a low variable of siteA but I'm trying use this variable on siteB so using {early_bird_discount} does not work here. Is there any possibility to get the global variable from siteA on siteB?

1 Answer 1


You could try two things:

One is to set this particular Low Variable as Early Parsed (in the variable settings). Then you can call it like this:

{exp:cartthrob:arithmetic expression="{option_price_numeric} -({option_price_numeric} * {early_bird_discount} / 100)"}

Or you could try adding parse="inward" to the arithmetic tag:

{exp:cartthrob:arithmetic parse="inward" expression="{option_price_numeric} -({option_price_numeric} * {exp:low_variables:single var='early_bird_discount'} / 100)"}
  • Yep. And I'd recommend the first option.
    – Low
    Feb 11, 2014 at 13:26
  • I have updated the description because there is still an error. Thanks for helping me out!
    – Pibble
    Feb 11, 2014 at 14:41
  • You should open up cartthrob/libraries/Math.php and var_dump($expression); in the evaluate function. If you do that, you should be able to see which unparsed tag is the culprit. Feb 11, 2014 at 15:15
  • You can also enable template debugging and look up the cartthrob:arithmetic tag, to see what the actual opening tag looks like. If the LV is parsed, you can rule that out as the culprit.
    – Low
    Feb 12, 2014 at 7:24
  • if I use {early_bird_date} this is the culprit. If I use {exp:low_variables:single var='siteA:early_bird_discount'} I get the following expression: 199.00 -(199.00 * M20o93H7pQ09L8X1t49cHY01Z5j4TT91fGfr / 100)
    – Pibble
    Feb 12, 2014 at 9:27

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