The One Dollar Word Challenge is built on a simple premise, which makes it accessible for students of any level. But there is more than one answer, which means that you can make it an on-going challenge that lasts all year. The best part is that students are practicing their addition facts over and over and don't even realize it!
You could use this tomorrow in class. The PDF includes a brief lesson plan, teacher notes, print-outs to make a bulletin board, and nearly 1,000 one dollar words.