Check the mode before you start
The most common calculator error in physics is the angle mode. For SPM Physics trigonometry, the calculator should be in degree mode (often shown as DEG). Check this at the start; a calculator left in radian mode gives wrong answers for sine, cosine and tangent even when your method is correct.
Enter standard form correctly
Physics is full of very large and very small numbers. Enter them with the exponent key (often labelled EXP, x10 to the power, or E), not by typing the digits for ten and a power. For example, key 3 then the exponent key then 8 for 3 times ten to the eighth, not 3 x 10 ^ 8, which is slower and error-prone. Watch negative powers carefully.
Respect the order of operations
Calculators follow mathematical order, so use brackets to make your intention clear:
- Put the whole denominator of a fraction in brackets.
- Bracket sums before squaring or dividing them.
- Check that a squared or square-root applies to what you intended.
A missing bracket is a frequent cause of answers that are wrong by a large factor.
Keep precision and use memory
Do not write down a rounded intermediate value and retype it; that adds error. Use the answer key (Ans) or memory to carry the full value into the next step, and round only the final answer.
Know the rules and practise on your own calculator
Use only a calculator model that the exam board permits; programmable or graphing calculators are generally not allowed, so check the current rules with your school or the official guidelines. Practise with the exact calculator you will bring, since keys and menus differ between models, and being fluent on your own device saves time and avoids mistakes in the exam.