Caitlin, these posters are lovely - the bright colors on the divisibility examples (like 312 divisible by 4) are exactly what a classroom wall needs for a topic students otherwise treat as dry rules. My pupils always struggled most with the rules for 7 and 11, so having those visible every day makes a real difference. I run factorcalculator.org, a free site with divisibility checks and factor/GCF calculators, and I like to pair wall displays like these with a quick digital self-check so students can test the rule on their own numbers. Great freebie - I'm printing the sample poster for my factors unit, and I'll be looking out for that PowerPoint and foldable review you mentioned!