Section 1
Custom Operation Definition
Property
A custom operation uses a symbol (like , , , ) to represent a specific mathematical rule involving two variables. The general form is , where is the custom symbol.
In this Grade 4 AoPS Introduction to Algebra lesson, students learn how to define and evaluate custom operations — such as x ★ y or a # b — by treating them as two-variable functions and applying substitution. Drawing from Chapter 16 on Functions, the lesson covers how standard operations like addition and multiplication are simply functions in familiar notation, then challenges students with AMC and MATHCOUNTS problems involving nested operations and solving equations with custom-defined operators.
Section 1
Custom Operation Definition
A custom operation uses a symbol (like , , , ) to represent a specific mathematical rule involving two variables. The general form is , where is the custom symbol.
Section 2
Nested Custom Operations
When custom operations are nested, evaluate from the innermost operation outward, following the order of operations. For nested operations like , first evaluate , then apply the operation .
Section 3
Function Iteration vs Function Multiplication
Function iteration notation: means applying function exactly times, so
Function multiplication: means multiplying the output by itself
Section 4
Function Composition
The composition of functions f and g is written and is defined by
We read as of of . In composition, the output of one function is the input of a second function.
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Section 1
Custom Operation Definition
A custom operation uses a symbol (like , , , ) to represent a specific mathematical rule involving two variables. The general form is , where is the custom symbol.
Section 2
Nested Custom Operations
When custom operations are nested, evaluate from the innermost operation outward, following the order of operations. For nested operations like , first evaluate , then apply the operation .
Section 3
Function Iteration vs Function Multiplication
Function iteration notation: means applying function exactly times, so
Function multiplication: means multiplying the output by itself
Section 4
Function Composition
The composition of functions f and g is written and is defined by
We read as of of . In composition, the output of one function is the input of a second function.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter