Calculation Shortcut( Week 44 Evaluation)
1. Find the result of 20 − 19 + 18 − 17 + 16 − 15 + 14 − 13 + 12 − 11 + 10 = ? 2. Find the result of 1 − 2 + 3 − 4 + 5 − 6 + 7 = ? 3. Find the result of 2 − 3 + 4 − 5 + 6 − 7 + 8 − 9 + 10 − 11 + 12 = ? 4. Find the result of 10 − 9 + 8 − 7 + 6 − 5 + 4 − 3 + 2 − 1 = ? 5. Find the result of 9 − 10 + 11 − 12 + 13 = ? 6. Find the sum of 2 + 4 + 6 + 8 = ? 7. Find the sum of 1 + 3 + 5 + 7 + 9 = ? 8. Find the sum of 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 = ?