IGCSE Maths G-1: Fractions, Decimals and Percentages | IGCSE 数学 G-1：分数、小数与百分数

📚 IGCSE Maths G-1: Fractions, Decimals and Percentages | IGCSE 数学 G-1：分数、小数与百分数

This guide covers the essential number skills required for IGCSE Mathematics Topic G-1. You will learn how to move confidently between fractions, decimals and percentages, perform calculations, and apply these skills to real-world problems. The content is designed for both classroom teaching and independent revision.

本指南涵盖 IGCSE 数学主题 G-1 所必需的核心数字运算技能。你将学会在分数、小数和百分数之间熟练转换，进行计算，并将这些技能应用到实际问题中。内容既适合课堂教学，也适合自主复习。

1. Understanding Fractions, Decimals and Percentages | 理解分数、小数与百分数

A fraction represents a part of a whole and is written as a/b, where a is the numerator and b is the denominator. The denominator shows how many equal parts the whole is divided into, and the numerator shows how many of those parts are taken. For example, 3/4 means 3 parts out of 4 equal parts.

分数表示整体的一部分，写作 a/b，其中 a 是分子，b 是分母。分母表示整体被分成多少等份，分子表示取了多少份。例如，3/4 表示 4 等份中的 3 份。

A decimal is another way of expressing a fraction with denominators of 10, 100, 1000 and so on. A percentage means “per hundred” and is represented by the symbol %. The same quantity can be written in all three forms. For instance, 1/2 = 0.5 = 50%.

小数是分母为 10、100、1000 等的分数的另一种表达方式。百分数表示 “每一百份”，用符号 % 表示。同一个数量可以用三种形式表示。例如，1/2 = 0.5 = 50%.

1/2 = 0.5 = 50%

2. Converting Between Forms | 三种形式之间的换算

To convert a fraction to a decimal, divide the numerator by the denominator. For example, 3/8 = 3 ÷ 8 = 0.375. To convert a decimal to a percentage, multiply by 100 and add the % sign, so 0.375 × 100 = 37.5%.

将分数转换为小数，用分子除以分母。例如，3/8 = 3 ÷ 8 = 0.375。将小数转换为百分数，乘以 100 并加上百分号，因此 0.375 × 100 = 37.5%.

To convert a percentage to a fraction, write the percentage over 100 and simplify if possible. For example, 65% = 65/100 = 13/20. To convert a percentage to a decimal, divide by 100, so 65% = 0.65.

将百分数转换为分数，把百分数写在 100 之上并化简。例如，65% = 65/100 = 13/20。将百分数转换为小数，除以 100，因此 65% = 0.65.