Students build subtraction fluency using dynamic flashcards that model subtraction on a number line. Learners flip through cards visualizing backward jumps along the number line to connect subtraction with counting back. This activity supports TEKS 3.4.A (represent subtraction) and aligns with Common Core 2.NBT.B.5.
Skills: subtraction fluency, number line modeling, counting back, number sense. Grades 3-5.