The starting point for everything - how to type an expression, get an answer, and reuse it.
In short: Entering a calculation means typing an expression into the calculator's home (or Calculator) screen exactly as it is written, then pressing ENTER (EXE on a Casio). The GDC follows the order of operations, so brackets matter. Check the expression on screen before pressing ENTER, so a typing slip does not become a wrong answer.
When you'd use this
Checking a value you've substituted into a formula, before writing the final answer down.
Quick arithmetic in the middle of a longer question, so you don't lose time doing it by hand.
The very first step on almost every calculator question - nothing else works until you can get a number out.
Building up a multi-step calculation using ANS to carry the previous result forward.
Here's a real IB-style question that uses exactly this technique.
EasyCalculatorPaper 2[2 marks]
Work out 3(2.4)² − 5 × 1.8, giving your answer to 3 significant figures.
8.28
Mark it
Correct2 / 2 marks
Worked solution & mark scheme:
M1 Substitute into 3(2.4)² − 5(1.8)
A1 8.28
Common questions
When would I need to enter a calculation on the home screen in IB Maths?
The starting point for everything - how to type an expression, get an answer, and reuse it. Checking a value you've substituted into a formula, before writing the final answer down. Quick arithmetic in the middle of a longer question, so you don't lose time doing it by hand.
How do I enter a calculation on the home screen on a TI-84 Plus CE?
1. Turn the calculator on and make sure you are on the home screen (not in a menu or app). 2. Press ON to turn on. Press 2nd → MODE (QUIT) or CLEAR to return to the home screen from any menu. 3. Type the expression using the number keys and operation keys (+, −, ×, ÷). Press ENTER / EXE to get the answer. 4. The last answer is stored and can be recalled - see 'Store a value and reuse it'.
How do I enter a calculation on the home screen on a Casio fx-CG50 and fx-CG100?
1. Turn the calculator on and make sure you are on the home screen (not in a menu or app). 2. Press ON. Press MENU to go to the main menu. Press EXIT or SHIFT+EXIT (QUIT) to back out of any screen. 3. Type the expression using the number keys and operation keys (+, −, ×, ÷). Press ENTER / EXE to get the answer. 4. The last answer is stored and can be recalled - see 'Store a value and reuse it'.
How do I enter a calculation on the home screen on a TI-Nspire CX?
1. Turn the calculator on and make sure you are on the home screen (not in a menu or app). 2. Press ON. Press ESC or ctrl+W to close a document and return to the home screen. Press ctrl+Z to undo if you made a mistake. 3. Type the expression using the number keys and operation keys (+, −, ×, ÷). Press ENTER / EXE to get the answer. 4. The last answer is stored and can be recalled - see 'Store a value and reuse it'.
What should I watch out for when I enter a calculation on the home screen?
If the calculator is unresponsive or showing unexpected symbols, press CLEAR (TI-84) or ESC (Nspire) a few times to get back to a clean input.
How are marks awarded when I enter a calculation on the home screen in an IB exam?
In the worked example on this page (2 marks, Paper 2), the marks are: M1: Substitute into 3(2.4)² − 5(1.8); A1: 8.28.
