There are three ways to share. We can share what we have equally, or equitably or justly. That is each person can get the same amount as all others, or we can give each person what they need or we can provide a share based on what we think is right.
This is not so hard to do with real pies. The economic pie is far more complex. Dividing a peach pie gives each person a treat. But dividing the economic pie can mean the difference between subsistence and civilization.
What we might think just or fair or equal may not make sense from the standpoint of results. Picking a General to command an army needs to be based on merit. When having an examination or conducting a test, equality is required otherwise the results will not mean much. But what about when we are dealing with economic factors such as jobs and other economic resources. Is it best to do what we think just? Do we give everyone an equal chance at every job? Or do we seek to guide the most able into the most suitable spot?