I use this MS PowerPoint presentation file to introduce the Product-Sum Method of factoring trinomials with a leading coefficient = 1 in my 8th and 9th grade Math I classes. It reviews in detail the Product-Sum Method of factoring of trinomials and includes a mnemonic to help students remember the factoring steps. It is a totally animated ppt file (also includes some audio) and it is very easy for students to understand and more importantly remember. Any of the ppt animations can be modified as desired by the presenter (teacher). It includes 4 example problems that cover all of the trinomial term sign types (i.e., all positive, all negative and one positive and one negative). It also includes 3 trinomial examples at the end for the students to complete if desired by the teacher. I always print out a copy of my ppt files for my students to retain in their math notebooks and to jot notes on while showing the slides.