Compound expression vs. Expression vs. Sub-expression
I feel I got a little confused here distinguishing sub-expression from expression.

`Compound expression` - An expression involving more than one operator.

E.g. `1 + 1 * 1`

`Expression` - An operator with one or more operands.

E.g `1 + 1` or `+ 1`

is there a level below the expression which is called a sub-expression?

Compound expression vs. Expression vs. Sub-expression
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I feel I got a little confused here distinguishing sub-expression from expression.

`Compound expression` - An expression involving more than one operator.

E.g. `1 + 1 * 1`

`Expression` - An operator with one or more operands.

E.g `1 + 1` or `+ 1`

is there a level below the expression which is called a sub-expression?
