Choosing the right topic
If you are not sure which strand to pick, start with what your students just finished. After a unit on adding two-digit numbers, look in Operations & Algebraic Thinking for spiral-review pages, then peek at Place Value & Base Ten for the underlying skill they will need next. The two strands intentionally overlap in the early grades, which is why our pages cross-link between them.
For older students, the Ratios & Proportional Reasoning and Expressions & Equations strands form the bridge between arithmetic and algebra. A student who can confidently solve a one-step ratio table is much closer to solving a one-step equation than they realize. For more curriculum guidance, see this K-8 math scope and sequence guide.
If you are working with a struggling student, prefer the Intro and Practice difficulty pages within a topic. If you are differentiating for an advanced learner, the Mastery and Challenge pages add small twists like missing-addend layouts, multi-step word problems, and number-line reasoning prompts.