#例程2：数字运算
b = 5
c = 4
d = -b*c+b*10
print("%\n",d)
b = 5c = 4d = -b*c+b*10/2
print("%\n",d)
b = 5
c = 4
d = -b*c+b**3print("%\n",d)
a = 5b = 3c = 2d = a+5*(b<<1)**c
print("%.2f\n",d)