Sequence of calculation

I need the computed field to calculate from other computed field's values. The example is:

computed_field_1 = field_a + field_b + field_c
computed_field_2 = computed_field_1 + field_d
computed_field_3 = (computed_field_2 * 0.875) + field_e +computed_field_1

the problem is I cannot define the sequence of calculation of computed fields when I first save a node, the computed_field_3 see the value of computed_field_1 and computed_field_2 being null and the secondary result in computed_field_3 appears incorrect.

My solution of this problem is rewrite all calculations in each computed field without referring other computed fields but the code will be much longer. Is there any better way of doing this?

Thanks