This is an idea that stemmed from my students' low test scores. While students knew the process by which to answer math questions, their fluency in addition (as well as subtraction, multiplication and division) was such that they were hindered on tests. This set of 36 addition problems presented in a timed fashion allowed them to build fluency over time. I saw large increases in standardized test scored because fewer computational errors were made. Enjoy, and if you like this one, check out my subtraction, multiplication and division versions coming soon!