Karabiner XML for mapping fn+- (fn-hyphen) to a legitimate minus sign, cobbled together from sone online sources I forget

fn_minus.xml

<?xml version="1.0"?>
<root>
  <item>
    <name>Change fn+- to (minus sign)</name>
    <appendix>You need to enable Unicode Hex Input and U.S. input sources.</appendix>
    <identifier>private.fn_minus</identifier>
    <autogen>__KeyToKey__
      KeyCode::MINUS, ModifierFlag::FN,

      <!-- change input source to Unicode -->
      KeyCode::VK_CHANGE_INPUTSOURCE_UNICODEHEXINPUT,

      <!-- wait until input source was changed -->
      KeyCode::VK_WAIT_10MS,
      KeyCode::VK_WAIT_10MS,
      KeyCode::VK_WAIT_10MS,

      <!-- put minus -->
      KeyCode::KEY_2, ModifierFlag::OPTION_L,
      KeyCode::KEY_2, ModifierFlag::OPTION_L,
      KeyCode::KEY_1, ModifierFlag::OPTION_L,
      KeyCode::KEY_2, ModifierFlag::OPTION_L,

      <!-- restore input source -->
      KeyCode::VK_CHANGE_INPUTSOURCE_US,

      <!-- suppress key repeating -->
      Option::NOREPEAT,
    </autogen>
  </item>

</root>