BA II Plus setup: the four settings to fix before you practise
Decimal places, payments per year, compounding periods and the AOS setting — get these wrong and every TVM answer is quietly wrong too.
4 min read
Why setup matters more than keystrokes
The BA II Plus ships with two defaults that are wrong for actuarial work: two decimal places, and twelve payments per year. The first hides the digits you need to compare against five printed options; the second silently converts every interest rate you enter into a monthly one. Both persist through a reset of the worksheet you are in, so fix them once and check them before every practice session.
The four settings
Each of these is a short sequence in the FORMAT and P/Y menus. Nothing else in setup is worth changing.
| Keys | Effect |
|---|---|
| 2ND · FORMAT · 9 · ENTER | Display nine decimal places, so intermediate values are not rounded on screen. |
| ↓ ↓ ↓ (to DEG/CHN) · 2ND · SET | Confirm chain (CHN) or algebraic (AOS) entry — pick one and always use it. |
| 2ND · P/Y · 1 · ENTER | One payment per year. C/Y follows P/Y unless you change it separately. |
| ↓ · 1 · ENTER · 2ND · QUIT | One compounding period per year, then leave the menu. |
The sign convention
The TVM keys enforce a cash-flow sign convention: money you receive is positive and money you pay is negative. A loan is therefore PV positive and PMT negative, or PV negative and PMT positive, but never both the same sign. If the calculator returns an answer with an unexpected sign, the convention is telling you which side of the transaction it thinks you are on.
Resetting between questions
2ND · CLR TVM clears the five TVM registers but leaves P/Y, C/Y and the display format alone — which is what you want. A full 2ND · RESET · ENTER restores the factory defaults, including the two settings you just fixed, so keep it for emergencies.