I mistakenly added 0.42 which should have subtracted from a number, and I ended up with 0.9. How much would it be if I counted correctly?
0.9 0.42 [OP_SUB] 0.42 [OP_SUB]
var_a = 0.9
var_b = 0.42
var_c = var_a - var_b
var_d = 0.42
var_e = var_c - var_d
print('{:.2f}'.format(round(var_e+1e-10,2)))