What is Balance of Trade? In which situations is it favourable and unfavourable?

What is Balance of Trade? In which situations is it favourable and unfavourable?

The Balance of Trade of a country is the difference between its export and import.
In following situations, it is favourable and unfavourable
(i) When the value of export exceeds the value of imports, it is called a favourable balance of trade.
(ii) On the contrary, if the value of imports exceeds the value of exports, it is termed as unfavourable balance of trade.