6.61 How to sort a list of numbers?

Sort[] sorts numbers from small to large by default. By supplying a function, one can change this as needed

lst = {1, 2, 5, 3, 7}; 
Sort[lst] 
Out[255]= {1, 2, 3, 5, 7} 
 
Sort[lst, #1 < #2 & ] 
Out[256]= {1, 2, 3, 5, 7} 
 
Sort[lst, #1 > #2 & ] 
Out[257]= {7, 5, 3, 2, 1}