Could you please explain the difference in meaning between ajoute and rajoute, according to Collins On Line Dictionary they both mean the same thing. Here are the 2 answers from the exercise: -
À la fin, elle rajoute de la cannelle.' 'A la fin, elle ajoute de la cannelle.'
ALSO in the two sentences, one of them has A and the other has À. Is this an error? If not please explain why both are correct.