diff --git a/api/custom_functions_you_can_override.lua b/api/custom_functions_you_can_override.lua
index d815b1e..bfb02dc 100644
--- a/api/custom_functions_you_can_override.lua
+++ b/api/custom_functions_you_can_override.lua
@@ -568,6 +568,76 @@ yl_speak_up.custom_functions_r_[ "set_variable_to_random_value_from_list" ] = {
 }
 
 
+yl_speak_up.custom_functions_r_[ "var0_eq_var1_op_var2" ] = {
+	description = "Set a <variable0> to the value of <variable1> <operator> <variable2>.",
+	param1_text = "Name of the variable0 to set:",
+	param1_desc = "Which variable do you want to set to the new value?",
+	param2_text = "Name of variable1:",
+	param2_desc = "Which variable holds the value of the first operand?",
+	param3_text = "Operand (+ - * / % ^ and or):",
+	param3_desc = "Choose operand: Add, subtract, multiply, divide, modulo, exponent, and, or.",
+	param4_text = "Name of variable2:",
+	param4_desc = "Which variable holds the value of the second operand?",
+	code = function(player, n_id, r)
+		if(not(r) or not(r.r_param1) or r.r_param1 == ""
+		  or not(r.r_param2) or r.r_param2 == ""
+		  or not(r.r_param3) or r.r_param3 == ""
+		  or not(r.r_param4) or r.r_param4 == "") then
+			return false
+		end
+		-- the owner is already encoded in the variable name
+		local pname = player:get_player_name()
+		local owner = yl_speak_up.npc_owner[ n_id ]
+		local prefix = "$ "..tostring(owner).." "
+		local v_1 = yl_speak_up.get_quest_variable_value(pname, prefix..r.r_param2)
+		local v_2 = yl_speak_up.get_quest_variable_value(pname, prefix..r.r_param3)
+		local new_value = nil
+		local op = r.r_param3
+		if(op == 'and') then
+			new_value = v_1 and v_2
+		elseif(op == 'or') then
+			new_value = v_1 or v_2
+		else
+			v_1 = tonumber(v_1)
+			v_2 = tonumber(v_2)
+			if(v_1 == nil or v_2 == nil) then
+				new_value = nil
+			elseif(op == '+') then
+				new_value = v_1 + v_2
+			elseif(op == '-') then
+				new_value = v_1 - v_2
+			elseif(op == '*') then
+				new_value = v_1 * v_2
+			elseif(op == '/') then
+				if(v_2 ~= 0) then
+					new_value = v_1 / v_2
+				else
+					new_value = nil
+				end
+			elseif(op == '%') then
+				if(v_2 ~= 0) then
+					new_value = v_1 % v_2
+				else
+					new_value = nil
+				end
+			elseif(op == '^') then
+				new_value = v_1 ^ v_2
+			end
+		end
+		if(new_value == nil) then
+			return false
+		end
+		local ret = yl_speak_up.set_quest_variable_value(pname, prefix..r.r_param1, new_value)
+
+		local o_id = yl_speak_up.speak_to[pname].o_id or "?"
+		yl_speak_up.debug_msg(player, n_id, o_id, tostring(r.r_id).." "..
+			"state: Success: "..tostring(ret).." for setting "..tostring(r.r_param1).." to "..
+			tostring(new_value)..".")
+		return ret
+	end
+}
+
+
 yl_speak_up.custom_functions_r_[ "play_sound" ] = {
 	description = "Plays a sound.",
 	param1_text = "Name of the sound(file):",