Which is better of these two class diagrams calculator ?

Question

I'm a novice programmer i draw two class diagrams for calculator Project, i want you to check each one of them and tell me which one is better and also, i would appreciate it if you point out the parts that are wrong or could be better.

 

https://s8.postimg.org/5l3953cgl/Class78.jpg

 

https://s7.postimg.org/rd3jtyzhn/class2.png