[Grammar] Distributive expression

[Snappy]

There are several sheets of paper and envelopes.
If I want people to put a sheet of paper into an envelope, another sheet of paper into another envelope,... (i.e., each envelope will contain one sheet of paper), which one of the following expressions is proper?

Put a sheet each into a separate envelope.
Put a sheet each into separate envelopes.

 

[MASM]

There are several sheets of paper and envelopes.
If I want people to put a sheet of paper into an envelope, another sheet of paper into another envelope,... (i.e., each envelope will contain one sheet of paper), which one of the following expressions is proper?

Put a sheet each into a separate envelope.
Put a sheet each into separate envelopes.

You could say: "Put one sheet of paper in each envelope"