This PPT gives students practice using algebra tiles to model expressions and is aligned to the Common Core for 7th grade math. In addition to asking students to model using algebra tiles, other slides require students to combine like terms. Answer slides are provided when students combine terms and are given using the additive inverse or just subtraction. The PowerPoint only features questions and answers, so if you're looking for a visual representation or for explanations on the slides, this will not meet your needs. I would use these questions for review and practice after you've already taught the content.