How Atom Economy Is calculated

It should be noted that the calculation considers only the reactants and ignores intermediates made in one step or stage and consumed in the next. Because of this, one must not multiply the atom economy ofeach stage to produce an overall atom economy for a synthetic scheme. Overall atom economy must be calculated as follows  

Synthetic schemes with two or more separate branches are treated analogously by taking into account all of the reactants but none of the intermediates in the calculation. Thus, for the following branched synthetic process  

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