3 +  5
 = 8
70 / 12
 = 5
80 - 20
 = 60
700 / 100
 = 7
10 * 15
 = 150
 82 -- 5
 = 87
 * 89 92
 ==> Error: invalid syntax (<string>, line 1)
 a + b
 ==> Error: name 'a' is not defined
** 12 % 15
 ==> Error: invalid syntax (<string>, line 1)
6+5
 = 11
-------
 ==> Error: invalid syntax (<string>, line 1)
9 / 0
 ==> Error: integer division or modulo by zero
6 - 10
 = -4

 ==> Error: unexpected EOF while parsing (<string>, line 1)
7.8 * 2.3
 = 17.94
****************
 ==> Error: invalid syntax (<string>, line 1)
18  + 17
 = 35
-7 + -9
 = -16
-10 * -12
 = 120
-13.45 / 7.62
 = -1.76509186352
250.4 - 17.9
 = 232.5
5 / 0 ==> Error: integer division or modulo by zero