Final answer:
To remove negative tiles when only positive tiles are present in mathematics, introduce equal numbers of positive and negative tiles (zero pairs) and then remove the needed negative tiles. This allows for the operation without altering the value of the collection.
Step-by-step explanation:
It seems that you are referring to a concept in mathematics that deals with manipulative tiles or counters in learning algebra, often used in middle school math classrooms to visually represent equations and inequalities.
When dealing with positive tiles only and the need arises to remove negative tiles, which are not present, you typically have to introduce a pair of opposites to facilitate this. For example, if you need to subtract -3 tiles and you only have positive tiles, you can add 3 positive and 3 negative tiles to the collection. Because a positive and a negative tile together are equal to zero (they cancel each other out), you have not changed the value of the collection. Now you can remove the 3 negative tiles as required.
This technique is often referred to as adding a zero pair. A zero pair consists of one positive and one negative tile, which together equal zero. By adding and then removing a zero pair, you can effectively remove negative tiles without changing the overall value of the tile collection.