You subtracted 4.3 when you should have added 4.3 to a number, resulting in 8.8. Find the correct value.
8.8 4.3 [OP_ADD] 4.3 [OP_ADD]
var_a = 8.8
var_b = 4.3
var_c = var_a + var_b
var_d = 4.3
var_e = var_c + var_d
print('{:.2f}'.format(round(var_e+1e-10,2)))