Students recognize equality as a relationship between two equal quantities and solve simple addition and subtraction equations with unknowns in any position using whole numbers and sums or differences within 20. They identify, create, compare, describe, and extend repeating and growing patterns with objects, shapes, colors, sounds, and small numbers, applying simple rules to predict missing or next elements and informally recognize odd-even alternation. They extend and identify number patterns by 1, 2, 5, and 10 within 0–100, use number charts and number lines to describe these relationships, and find or apply simple add-or-subtract input-output rules with familiar whole numbers.