3 +  5 -->Eror!
70 / 12 = 5
80 - 20 = 60
700 / 100 = 7
10 * 15 = 150
 82 -- 5 -->Eror!
 * 89 92 -->Eror!
 a + b -->Eror!
** 12 % 15 -->Eror!
6+5 -->Eror!
------- -->Eror!
9 / 0 -->Eror!
6 - 10 = -4
 -->Eror!
7.8 * 2.3 = 17.94
**************** -->Eror!
18  + 17 -->Eror!
-7 + -9 = -16
-10 * -12 = 120
-13.45 / 7.62 = -1.76509186352
250.4 - 17.9 = 232.5
5 / 0 -->Eror!