Fixing a typo is faster than retyping - especially for long expressions.
In short: Editing a calculation means recalling an earlier entry and changing it instead of retyping everything. Use the arrow keys, the entry history or the last-answer key to bring the expression back, change the wrong value and press ENTER again. This saves time in a long Paper 2 question and avoids introducing new typing errors.
| TI-84 Plus CE | Casio fx-CG50 and fx-CG100 | TI-Nspire CX | |
|---|---|---|---|
| Key sequence | Press 2nd → ENTER (ENTRY) to recall the last expression. Move with ◄ ► arrow keys. DEL deletes the character under the cursor; 2nd → DEL (INS) inserts. Press CLEAR to wipe the line. | Press ◄ to go back into the previous entry. Use ◄ ► to move; DEL removes the character to the left. AC/ON clears everything. | Use ◄ ► to move within the expression. Backspace (◄ + DEL) deletes left. ctrl+Z undoes the last change. ctrl+R redoes. |
Tip: Recalling and editing is much faster than retyping - especially useful when you've made one small mistake in a long expression.
Tip: Recalling and editing is much faster than retyping - especially useful when you've made one small mistake in a long expression.
Tip: Recalling and editing is much faster than retyping - especially useful when you've made one small mistake in a long expression.
Here's a real IB-style question that uses exactly this technique.
Evaluate 2^(3 + 5) × 2.
Fixing a typo is faster than retyping - especially for long expressions. Fixing one small typo in a long expression, instead of retyping the whole thing. Re-running the same calculation with one number changed, e.g. trying a different value of x.
1. Use the arrow keys to move the cursor within the expression. 2. Press 2nd → ENTER (ENTRY) to recall the last expression. Move with ◄ ► arrow keys. DEL deletes the character under the cursor; 2nd → DEL (INS) inserts. Press CLEAR to wipe the line. 3. To reuse a previous calculation: recall it (see above), edit as needed, and press ENTER/EXE again.
1. Use the arrow keys to move the cursor within the expression. 2. Press ◄ to go back into the previous entry. Use ◄ ► to move; DEL removes the character to the left. AC/ON clears everything. 3. To reuse a previous calculation: recall it (see above), edit as needed, and press ENTER/EXE again.
1. Use the arrow keys to move the cursor within the expression. 2. Use ◄ ► to move within the expression. Backspace (◄ + DEL) deletes left. ctrl+Z undoes the last change. ctrl+R redoes. 3. To reuse a previous calculation: recall it (see above), edit as needed, and press ENTER/EXE again.
Recalling and editing is much faster than retyping - especially useful when you've made one small mistake in a long expression.
In the worked example on this page (2 marks, Paper 1), the marks are: M1: Correct order: exponent evaluated first, 2^8; A1: 512.
Questions that need this technique link back to this guide. Try one in practice mode, or see every GDC guide.