数学题：一块长方形铁皮，从四个脚各切掉一个边长为5厘米的正方形，然后做成盒子。（长方形的长为30厘米，宽为25厘米）这个盒子用了多少铁皮？它的容积有多大？（如下图）

数学题解答：

1.用的铁皮面积：30×25-5×5×4=650(平方厘米)

2.盒子的容积：（30-5-5）×（25-5-5）×5=1500（立方厘米）

推荐阅读：
C++ Coding Reference: next_permutation() and prev_permutation()　 C++ Coding Reference: count and count_if　 How to Reorder Data in Log Files using the Custom Sorting Algori　 C++ Coding Reference: std::accumulate() and examples　 C++ Coding Reference: sort() and stable_sort()　 The C++ Function using STL to Check Duplicate Elements/Character　 How to Find Positive Integer Solution for a Given Equation using　 How to Implement the instanceof in Javascript?　 Azerbaijani Blogger, Mehman Huseynov Sentenced To Prison For All　 Fitness Blog Shows Us All How Transformation Photos Can Be Decei