"Boys eat bread."
Translation:Drenge spiser brød.
"spiser" is the present tense form of the verb and "spise" is the infinitive form of the verb which is often used by dictionaries. http://ordnet.dk/ddo/ordbog?select=spise,2=spiser but for this word "spise" is also a noun I think. http://ordnet.dk/ddo/ordbog?select=spise,1=spiser
http://www.freelang.net/online/danish.php?lg=gb This one is Danish to English or English to Danish, but when I put in "spiser" it gives "dining", so I put in "spise" and I found more information as the infinitive is usually the best thing to enter into a dictionary. "at spise" is "to eat" (So "spise" must be what we call the "bare infinitive" without the "to" which is also how we look up verbs in our dictionary) according to the Tips and Notes which you can scroll down here to see: https://www.duolingo.com/skill/da/Basics-1
They don't sound the same. Train your ear by listening to native speakers here: http://forvo.com/search/dreng%20drenge%20drengen%20drengene/
"æde" is a unmannerly version of eat, often used whe it is animals thst eat something. "spise" is normaly used when it is people who eat the food.
Koen æder gras = The cow eats grass.
That being said "æde" can still be used in some cases where people eat (often if it is about large amounts of food), and it is not really wrong to use "spise" when talking about animals eating.
So you do not really need to use the word "æde" yourself, but at least you know the word if others use it.