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1 Primary & Middle School Mathematics1–9 年级在线 2 High School Mathematics10–12 年级在线 3 University Mathematics — Year 1本科一年级在线 4 University Mathematics — Year 2本科二年级在线 5 University Mathematics — Year 3本科三年级在线

1 Primary & Middle School Physics1–9 年级在线 2 High School Physics10–12 年级在线 3 University Physics — Year 1本科一年级在线 4 University Physics — Year 2本科二年级在线 5 University Physics — Year 3本科三年级在线

1 School Chemistry — Grades 1 to 121–12 年级在线 2 University Chemistry — Year 1本科一年级在线 3 University Chemistry — Year 2本科二年级在线 4 University Chemistry — Year 3本科三年级在线

1 Primary & Middle School Biology1–9 年级在线 2 High School Biology10–12 年级在线 3 University Biology — Year 1本科一年级在线 4 University Biology — Year 2本科二年级在线 5 University Biology — Year 3本科三年级在线

1 Primary & Middle School Earth and Space Sciences1–9 年级在线 2 High School Earth and Space Sciences10–12 年级在线 3 University Earth and Space Sciences — Year 1本科一年级在线 4 University Earth and Space Sciences — Year 2本科二年级在线 5 University Earth and Space Sciences — Year 3本科三年级在线

1 Markets I: The Ecosystem and Exchange-Traded Markets市场在线 2 Markets II: Rates, FX and Credit市场在线 3 Markets III: Commodities, Energy and Crypto市场在线 4 Quantitative Methods方法在线 5 Derivatives and Volatility衍生品在线 6 Rates, Credit, XVA and Risk利率、信用与风险在线 7 Research Craft: Predictors, Backtests, Measurement, Portfolios研究在线 8 Strategies I: Equities and Futures策略在线 9 Strategies II: Volatility, Relative Value, Macro and the Bank Desks策略在线 10 Microstructure and Execution交易执行在线 11 Market Making and High-Frequency Trading做市在线 12 Machine Learning for Markets机器学习在线 13 Low-Latency Software技术在线 14 Networks, Hardware and Trading Infrastructure技术在线 15 Research, Data and Risk Platforms技术在线 16 The Desk and the Firm公司运营在线 17 The Industry: Firms, Roles and Careers职业发展在线 18 Interviews I: Maths, Probability and Speed职业发展在线 19 Interviews II: Markets, Trading Games and the Final Round职业发展在线 20 Interviews III: Code职业发展在线

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Mathematics · 术语表

什么是 Multiplication？

又称： product

Definition 10.1 Primary & Middle School Mathematics · 第 10 章 — Multiplication: First Steps

$4 \times 3$ means “four times three”:

4 \times 3 = 3 + 3 + 3 + 3 = 12 .

The sign is $\times$ , read “times”. The answer is the product (multiplication grows up in Chapter 16).

An array: 4 rows of 3. Counting by rows gives 4 × 3; the same dots by columns give 3 × 4 — so the order does not matter. — An array: $4$ rows of $3$ . Counting by rows gives $4 \times 3$ ; the same dots by columns give $3 \times 4$ — so the order does not matter.

示例

Example 10.2 (Order does not matter)

$4 \times 3$ and $3 \times 4$ count the same $12$ dots, one by rows, one by columns. Turning the array on its side proves it. So learning one product gives its twin for free.

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Definition 16.1 Primary & Middle School Mathematics · 第 16 章 — Multiplication

The product $3 \times 7$ means “three times seven”:

3 \times 7 = 7 + 7 + 7 = 21 .

On a picture, $3 \times 7$ is a rectangle of dots: $3$ rows of $7$ dots.

The same 21 dots, counted by rows or by columns: the order of a product does not matter. Knowing 3 × 7 gives 7 × 3 for free — half the tables to learn! — The same $21$ dots, counted by rows or by columns: the order of a product does not matter. Knowing $3 \times 7$ gives $7 \times 3$ for free — half the tables to learn!

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