约分就是分子分母可以除以相同的数，然后得到简化后的分数。
约分步骤如下：
1.将分子分母分解因数；
2.找出分子分母公因数；
3.消去非零公因数。
约分时，如果能很快看出分子和分母的最大公因数,直接用它们的最大公约数去除比较简便。
“分数的分子和分母同时除以一个相同的数（0除外），分数的大小不变——分数的基本性质”来进行约分。
方法一：可以用分子和分母的公因数（1除外）去除
例： /iknow-pic.cdn.bcebos.com/21a4462309f790529af05ddc00f3d7ca7acbd560"target="_blank"title="点击查看大图"class="ikqb_img_alink">/iknow-pic.cdn.bcebos.com/21a4462309f790529af05ddc00f3d7ca7acbd560?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto"esrc="https://iknow-pic.cdn.bcebos.com/21a4462309f790529af05ddc00f3d7ca7acbd560"/>，/iknow-pic.cdn.bcebos.com/9c16fdfaaf51f3dee1d4bc8698eef01f3b2979e9"target="_blank"title="点击查看大图"class="ikqb_img_alink">/iknow-pic.cdn.bcebos.com/9c16fdfaaf51f3dee1d4bc8698eef01f3b2979e9?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto"esrc="https://iknow-pic.cdn.bcebos.com/9c16fdfaaf51f3dee1d4bc8698eef01f3b2979e9"/>，则/iknow-pic.cdn.bcebos.com/d01373f082025aaf10ce7b29f7edab64024f1a57"target="_blank"title="点击查看大图"class="ikqb_img_alink">/iknow-pic.cdn.bcebos.com/d01373f082025aaf10ce7b29f7edab64024f1a57?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto"esrc="https://iknow-pic.cdn.bcebos.com/d01373f082025aaf10ce7b29f7edab64024f1a57"/>就是最简分数
像这样，把一个分数化成和它相等，但分子和分母都比较小的分数叫做约分（一般要化成最简分数）
方法二：直接用分数的分子和分母的最大公因数（1除外）去除
例： /iknow-pic.cdn.bcebos.com/91ef76c6a7efce1bccbdcd28a351f3deb58f65b9"target="_blank"title="点击查看大图"class="ikqb_img_alink">/iknow-pic.cdn.bcebos.com/91ef76c6a7efce1bccbdcd28a351f3deb58f65b9?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto"esrc="https://iknow-pic.cdn.bcebos.com/91ef76c6a7efce1bccbdcd28a351f3deb58f65b9"/>则/iknow-pic.cdn.bcebos.com/32fa828ba61ea8d38b5a71e69b0a304e241f58d3"target="_blank"title="点击查看大图"class="ikqb_img_alink">/iknow-pic.cdn.bcebos.com/32fa828ba61ea8d38b5a71e69b0a304e241f58d3?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto"esrc="https://iknow-pic.cdn.bcebos.com/32fa828ba61ea8d38b5a71e69b0a304e241f58d3"/>就是最简分数
小结：一般用分子和分母的公因数（1除外）去除分数的分子和分母，通常要除到最简分数为止。