第45页聪明小屋答案
1.1 × 1.1 - 1 × 1.2 = 1.1 × 1.1 - (1.1 - 0.1) × (1.1 + 0.1) = 0.01
1.2 × 1.2 - 1.1 × 1.3 = 1.2 × 1.2 - (1.2 - 0.1) × (1.2 + 0.1) = 0.01
1.3 × 1.3 - 1.2 × 1.4 = 1.3 × 1.3 - (1.3 - 0.1) × (1.3 + 0.1) = 0.01
发现规律:a × a - (a - 0.1) × (a + 0.1) = 0.1
例如:1.6 × 1.6 - 1.5 × 1.7 = 0.01
2.5 × 2.5 - 2.4 × 2.6 = 0.01
8.7 × 8.7 - 8.6 × 8.8 = 0.01
………