Mathematics
What the Mathematics domain tests
The Mathematics domain covers ratios and proportional relationships, the number system, expressions and equations, geometry, and statistics/probability. Items often require choosing a model or explaining a result, not only computing.
Core rules and concepts
- Follow order of operations and use inverse operations to isolate a variable.
- Distribute carefully: -(x - 3) = -x + 3, not -x - 3.
- A proportional relationship has the form y = kx; k is the constant of proportionality.
- Know formulas: area, circumference, Pythagorean theorem, and volume of prisms/cylinders.
- For data, compare mean and median; outliers pull the mean more than the median.
Worked example. Solve 3(x - 2) = 2x + 7. Distribute: 3x - 6 = 2x + 7. Subtract 2x: x - 6 = 7. Add 6: x = 13. Check: 3(11) = 33 and 2(13) + 7 = 33.
Traps that cost marks
- Dropping a negative sign when distributing or subtracting.
- Using diameter as radius in circle formulas.
- Confusing percent increase with 'percent of.'
- Choosing mean when an outlier makes median more representative.
- Forgetting units or rounding too early.