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Mathematics · 术语表

什么是 Half, third, quarter?

又称: half · quarter

Definition 17.7 Primary & Middle School Mathematics · 第 17 章 — Sharing and Division

The half of a number is the result of dividing it by 22; the third, by 33; the quarter, by 44. For instance the half of 1818 is 99, the third of 1818 is 66, the quarter of 3636 is 99.

示例

Example 17.8 (Doubles and halves go together)

The half of 4646: since 46=40+646 = 40 + 6, half of each part gives 20+3=2320 + 3 = 23. Check with the double: 23+23=4623 + 23 = 46. Knowing doubles by heart (25→5025 \to 50, 45→9045 \to 90, 150→300150 \to 300) makes halves instantaneous.

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