Input-Output Tables

Input-Output Tables

What students learn

Students learn how to read an input-output table, find the rule, and use the rule to fill in missing values. Start with Input-Output Tables: Find One Rule to see how one rule connects the table.

Why it matters

Input-output tables are an early step toward algebra because they show how one number changes when another number changes. Input-Output Tables: Multiply to Match helps students notice a multiplication rule, and Input-Output Tables: Divide to Reverse shows the matching reverse idea.

Learn the idea

The input is the number you start with, and the output is the number you get after applying the rule. A table helps students see that the same rule works again and again.

Try it

Ask the student to complete these pairs: 2 -> 6, 4 -> 12, 5 -> 15. Then ask what rule fits and how they know.

Parent guide

Keep the numbers small and ask the child to say the rule before writing it. If they guess, have them test the rule on a second row to see whether it still works.