Maybe it would work as a problem solving task? I do not know. But consider multiplying: one digits numbers -> one digit with two digit number -> two digit with 30 or other such -> two digit numbers with each other. Focus on understanding place value and use of the associative law (without naming it). Whole class discussions to share tactics.

Welcome to ME.SE! I added the undergrad education tag, please correct if this is not at university or similar institute.

Welcome to ME.SE! It is a really interesting question. Have you done a literature search and what kind of stuff have you found thus far?

@GeraldEdgar Yes, brackets are used as normal. But for multiplication of numbers one uses a symbol for multiplication between the numbers.

@Pedro The list of meanings of subtraction is from a textbook by van de Walle and others, intended for primary school teacher students.

The notation 2(3) is foreign to me in the Finnish, Norwegian and research mathematics contexts and would make a nice question, if it has not been asked already.

Hello, it is difficult for me to understand your question. Could you add something concrete there? Maybe a concrete problem and where you are struggling with it.