Grade 3 Unit 3: Addition and Subtraction The 20 days of warm-up slides intentionally spiral the major Grade 3 standards connected to addition, subtraction, rounding, multiplication, time, and multi-step reasoning. Daily routines such as number talks, decomposition tasks, visual drills, rounding prompts, clock-reading practice, and two-step word problems help students build fluency with adding and subtracting within 1,000 (3.NBT.A.2) while strengthening their understanding of place value and est