TI-84 Plus CE field manual for IB Math
Common mistakes to avoid
The wrong minus key, the wrong angle mode, the wrong standard deviation, and each device's own classic traps, and what each wrong answer looks like.
The wrong minus key. To type −5+8, start with , not . Start with the subtraction key and the calculator continues from your last answer: it writes Ans- for you, and with Ans = 20 you get 23 instead of 3. No error, just the wrong number.
An unbracketed denominator. The calculator follows the order of operations, not your reading order: 20/4×6 divides only by the 4 and gives 30. Dividing by the whole product needs brackets: 20/(4×6) is 65. Or use the fraction template ( , 1:n/d).
The exponent box holds the cursor. The key opens MATHPRINT's exponent box, and that box holds the cursor. Type 2^5 then +3 straight away, and the +3 lands in the exponent: 25+3=256, not 25+3=35. Press to drop back to the baseline before continuing the line.
The wrong angle mode. In RADIAN mode, sin(30) means 30 radians: a degrees problem comes back as −0.988: impossible for an acute angle, and the status bar said RADIAN all along. Switch it under (AI SL: DEGREE, once) and the same line gives sin(30∘)=0.5.
A fraction when you wanted a decimal. Enter with the fraction template and the answer comes back as a fraction: 32+61=65. When the question wants 3 significant figures, type instead (slash entry answers in decimals), or convert with , 2:▶Dec.
The wrong standard deviation. 1-Var Stats prints two: σx (divide by n) and Sx (divide by n−1). Which one an IB question wants depends on whether the data is the whole population (σx) or only a sample of it (Sx). And the variance is never printed: square the standard deviation yourself.