Start with an expression

Here is an expression that creates five sizes of “a”:

Wrap variables with Echo to print their intermediate values

Wrap i with Echo to print its intermediate values:

• Unlike Print, Echo returns the value that it echoes, so it can be wrapped around subexpressions without affecting evaluation.

Notes

Give an optional second argument to Echo to label the printed values:

Monitor and PrintTemporary can be used to print intermediate values of variables, but the printed output disappears when the evaluation finishes.