Students often make up their own rules in order to simplify solving math problems. Here are some of the doozies that I often encounter.
Always subtract the smaller fraction from the larger fraction. (Avoids borrowing from the whole number.)
When division is called for, always divide the larger number by the smaller number.
Step 1. Pick up the calculator.
Step 2. Look around for numbers (in the problem or wherever) to enter into the calculator.
Step 3: Seek help: "Do I multiply or divide?"
Step 4. Read the problem.
When the answer to a problem turns out to be a negative number, ignore the negative sign. (The rational: in real life, nothing has a negative value.)
John Schwarz