用简便方法计算.

$15.24$ ×99＋15.24＝（   ）

已知偶函数f（x）在（0，+∞）上为减函数，且f（2）=0，则不等式$\frac{f\left(x\right)+f\left(-x\right)}{x}>0$的解集为____ 

关于圆周率π，数学发展史上出现过许多很有创意的求法，如著名的浦丰实验和查理斯实验．受其启发，我们也可以通过设计下面的实验来估计π的值：先请120名同学，没人随机写下一个都小于1的正实数对（x，y）；再统计两数能与1构成钝角三角形三边的数对（x，y）的个数m；最后再根据统计数m估计π的值．假如统计结果是m=34，那么可以估计π≈____ （用分数表示）．

阅读短文，判断正确还是错误。

A letter

Here is a letter from Jim to his friend in the USA

Dear Lily:

    I am in China now. I go to school five days a week. The school and the food are good here. I have some Chinese friends. They are all very friendly to me. On Saturdays and Sundays we stay at home. In the afternoon we play games. My Chinese friends like English very much. They ask me to teach them English and they teach me Chinese. I like staying here.

    Please write soon!