When you divide the number by -2/3 and multiply it by -4/5, the result is -1/2. Find the unknown number at the beginning.
-1/2 -4/5 [OP_DIV] -2/3 [OP_MUL]
var_a = -0.5
var_b = -0.8
var_c = var_a / var_b
var_d = -0.6666666666666666
var_e = var_c * var_d
print('{:.2f}'.format(round(var_e+1e-10,2)))