Activity 2-1.3.1 Combining Like Terms with Algebra Tiles Algebra tiles can also be used when an expression contains negative terms. Black tiles represent the negative terms. Negative terms are terms that are being subtracted. Example 2: Simplify 2!!!-!2!!+!3!+!!!-!! using algebra tiles. First represent each term with algebra tiles. 2x2 - 2x 3 x - x2 Group the similar sized tiles together.