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课程 7 · 年级 5–7
Negative numbers and powers
📖 课程
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🎯 测验——选择翻译
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✅ 本课已完成
Below zero there are numbers too: −3 °C outside, −50 € in the account. Sign rules: minus times minus gives plus (−3 × −2 = 6), minus times plus gives minus. A power is fast multiplication: 2⁵ = 32. Special cases: any number to the power 0 = 1, and 10³ = 1000 — how big numbers are written.
- ●−5 + 8 = 3 (8 degrees warmer)
- ●−4 × −3 = 12 (minus × minus = plus)
- ●3⁴ = 81, 5³ = 125, 10⁶ = 1,000,000
🌡 City check: −2 °C in the morning, +5 °C at noon. The difference is 7 degrees, not 3!