here you called the
askTeller method that returns
returnBalance method .
myBalanceMethod holds the
returnBalance method not the result of calling
returnBalance method,you have to call it to make it any use.so here just called the
returnBalance method.you can't get result without calling the method.that's what parentheses do here.
and here you don't have parentheses after returnBalance.because we dont want the result of calling the
returnBalance method.with parentheses it'll give the result of' returnBalance' method.