2/1+5/4-2/1+5/4简便计算？

To simplify the expression 2/1 + 5/4 - 2/1 + 5/4, we need to find a common denominator for all four fractions before adding or subtracting them. The common denominator for 2/1 and 2/1 is 1, since both fractions already have the same denominator. The common denominator for 5/4 and 5/4 is 4, since both fractions already have the same denominator. Therefore, the simplified expression is: 2/1 + 5/4 - 2/1 + 5/4 = (2 + 5)/1 + (5 + 5)/4 = 7/1 + 10/4 = 7 + 10/4 = (7*4 + 10)/4 = (28 + 10)/4 = 38/4 = 19/2

朱丹分享道她两胎的生育都十分艰难，孕反严重，两次大出血，周一围听后不禁红了眼眶。， “这个时间段T3航站楼客流量比较大，T2航站楼客流量较小，我们就及时把T2航站楼的车调到T3航站楼。

内饰方面，第五代胜达进行了重新设计，配备了一体式大联屏，并在空调出风口下方保留了一些实体按键。，而服务收入从去年同期的7010万元缩减到5720万元。

对此，很多网友评价奚梦瑶跟何超欣的关系真的很不错，虽然是姑嫂关系，但是看起来更像是姐妹团。， 生活品质的更高追求，一直是科技发展的“向心力”。