explicitly separates the operations of arithmetic from the standardization of how a number is written or displayed.

The primary change is to think of conventional arithmetic operations like addition or multiplication as extremely simple: one parallel put together for addition, one parallel put inside for multiplication.

Separate from the operations of arithmetic is what we might normally call computation. Parens computation constructs a canonical form by alternating applications of parallel group and merge. Computation is implemented by one-to-one Pattern Matching and Substitution.