How to add and subtract complex numbers.
Using the number line to represent adding and subtracting whole numbers
Adding and subtracting polynomials with pictures or aligning vertically
How to add and subtract rational expressions.
Adding and subtracting fractions that have the same denominator, including a visual representation
Drawing pictures and procedures for adding or subtracting fractions with unlike denominators
How to add vectors geometrically two ways.
How to add or subtract polynomials.
How to add and subtract radical expressions.
How to add or subtract rational expressions.
Adding or subtracting decimals by vertically lining up the zeros
How to use simple matrix operations.
Adding or subtracting mixed numbers by either converting them to improper fractions or working with the integer part and the fractional part separately
How to simplify determinants using three row (or column) operations.
How to simplify square roots using two different methods.