1. The problem asks to perform subtraction similar to the examples given, where the second number is subtracted from the first number in the sequence. 2. The formula used is simple subtraction: $$a - b = c$$ where $a$ and $b$ are numbers from the sequence. 3. For each sequence, identify the first and second numbers to subtract. 4. Calculate each subtraction step-by-step: 1. For 7 9 8 4 2, subtract 9 - 2: $$9 - 2 = 7$$ 2. For 4 8 3 2 1, subtract 8 - 1: $$8 - 1 = 7$$ 3. For 6 9 2 8 5, subtract 9 - 5: $$9 - 5 = 4$$ 4. For 7 8 9 1 2, subtract 8 - 2: $$8 - 2 = 6$$ 5. For 4 3 9 8 1, subtract 9 - 1: $$9 - 1 = 8$$ 6. For 9 8 7 3 2, subtract 8 - 2: $$8 - 2 = 6$$ 7. For 10 9 6 7 5, subtract 9 - 5: $$9 - 5 = 4$$ 8. For 9 8 2 3 7, subtract 8 - 7: $$8 - 7 = 1$$ 9. For 10 8 4 3 9, subtract 8 - 9: $$8 - 9 = -1$$ 10. For 12 8 9 6 10, subtract 8 - 10: $$8 - 10 = -2$$ 5. Final answers: 1. 7 2. 7 3. 4 4. 6 5. 8 6. 6 7. 4 8. 1 9. -1 10. -2 This completes the subtraction operations as per the pattern shown in the examples.