If someone is missing someone badly, it could be because they haven't seen them in a long time. It could also mean they are in love with the person.
Bad is generally used as an adjective while badly is used as an adverb.
I miss you terribly, would be better.
"What is the difference between inequalities and equations" is a question, not a statement. A question cannot be true or false. It can be pointless, or badly phrased or misguided but that is a different matter.
"Missing" is not an action verb therefore should not be described by an adverb ( a word ending in ly). Likewise, "I feel badly" follows the same rule and is also grammatically incorrect.
Some words (verbs) used to say that someone is treated badly are:mistreatedmaligneddisrespectedexploitedabusedattackedwrongedharmedwoundedwronged
someone who judges someone about their race (badly)
Sven was badly injured by Hagger on Voltron. On Golions, he was killed.
it would be affected quite badly what with missing children and staff
Ahahahahaha someone wants it badly!
To wound someone badly and on purpose.
It depends on whether that someone is hurt badly.