欢迎学习分数！分数表示整体的一部分。上面的数字叫做分子，告诉我们有多少个部分。下面的数字叫做分母，告诉我们整体被分成多少个相等的部分。例如，在四分之三中，我们有四个相等部分中的三个部分。
现在让我们学习如何相加同分母的分数。规则很简单：当分母相同时，我们保持分母不变，只需要将分子相加。例如，四分之一加上四分之二等于四分之三。我们可以看到，一个部分加上两个部分等于三个部分，而分母四保持不变。
让我们总结一下今天学到的内容。分数表示整体的一部分。当我们要相加同分母的分数时，分母保持不变，只需要将分子相加。这个简单的规则适用于所有同分母分数的加法运算。
When fractions have different denominators, we need extra steps. First, find a common denominator. For one half plus one third, the common denominator is six. Next, convert each fraction: one half becomes three sixths, and one third becomes two sixths. Finally, add the numerators: three plus two equals five, giving us five sixths.
Let's work through a complete example. We want to add two thirds plus one fourth. First, find the least common multiple of three and four, which is twelve. Next, convert each fraction: two thirds becomes eight twelfths, and one fourth becomes three twelfths. Finally, add the numerators: eight plus three equals eleven, giving us eleven twelfths as our final answer.
Let's practice with two more examples. First, three fifths plus one tenth. Since ten is a multiple of five, we convert three fifths to six tenths, then add to get seven tenths. Second, one sixth plus two ninths. The least common multiple of six and nine is eighteen. One sixth becomes three eighteenths, and two ninths becomes four eighteenths. Adding gives us seven eighteenths.
To summarize what we have learned about adding fractions: Fractions represent parts of a whole. When denominators are the same, simply add the numerators and keep the denominator unchanged. When denominators are different, first find a common denominator, convert both fractions, then add the numerators. With practice, fraction addition becomes much easier.