How to Use a Scientific Calculator: Expressions, Ans, Variables and Memory

A scientific calculator does not work like a basic desk calculator that acts on each key press. You type the whole expression first and evaluate it in one go. Operator precedence and brackets apply exactly as written, so you can copy a formula from paper almost unchanged. This guide shows how to enter expressions in SciKey, how to reuse results (Ans, variables and memory), and how to choose a display format, using real examples.

1. Entering expressions

Use the on-screen keypad or your keyboard. The result preview updates as you type, and pressing Enter or = confirms the value and adds it to the history.

• Multiply with × or *, divide with ÷ or /, raise to a power with ^.
• Functions always need brackets: sin(30), not sin 30.
• Separate the arguments of two-argument functions with a comma: log(2, 8) = 3, nCr(5, 2) = 10.
• You can omit the multiplication sign between a number and a bracket, constant or function: 2π, 3(4+5) and 2sin(30) are all products.

Auto-closing brackets

Unclosed brackets at the end of an expression are closed for you. Type sin(30 and press Enter, and it is evaluated as sin(30). Handy, but only the very end gets closed. sqrt(9+16 + 1 becomes sqrt(9+16+1) = 5.0990, not sqrt(9+16) + 1 = 6. If a bracket needs to close in the middle, close it yourself.

2. Ans and chained calculations

Ans holds the last confirmed result, so you can keep going without retyping it.

• If an expression starts with an operator, Ans is inserted automatically. Typing ×2 right after a result gives Ans×2.
• You can also write Ans anywhere: sqrt(Ans), 1/Ans.

Example: compound growth. Find the growth factor for 8% a year over 10 years, then apply it to 1,000.

1. 1.08^10 → 2.15892499727
2. Type ×1000 (becomes Ans×1000) → 2158.92499727

3. Storing values in x, y and z with STO

Ans changes with every calculation. To keep a value for several steps, store it. With a result on screen, press [STO] then [x] (or y, z). From then on, writing x in an expression inserts that value, and you can attach it directly: 2x, πx^2.

Example: a block on a slope. A 12 kg block rests on a 30° incline with a kinetic friction coefficient of 0.2 (angle mode DEG).

1. 12×g0 → 117.6798 (weight in N; g0 is standard gravity, 9.80665 m/s²) → [STO][x]
2. x×sin(30) → 58.8399 (component along the slope) → [STO][y]
3. x×cos(30) → 101.913696312 (normal force) → [STO][z]
4. y − 0.2z → 38.4571607375 (net force after friction, N)
5. Ans/12 → 3.20476339479 (acceleration, m/s²)

Because you never copy intermediate values by hand, no rounding error creeps in. That habit matters in exams too.

4. Repeating a formula with different inputs

Example: areas of circles with radius 2.5, 4 and 7.5.

1. Enter 2.5 and confirm → [STO][x]
2. πx^2 → 19.6349540849
3. Confirm 4 → [STO][x], then tap πx^2 in the history to reload it and confirm → 50.2654824574
4. 7.5 → [STO][x] → πx^2 → 176.714586764

πx^2 means π×(x²) because powers bind tighter than implied multiplication. The history keeps your last 50 calculations in your browser's localStorage; tap an entry to reload its expression. Nothing is sent to a server.

5. Independent memory: M+, M−, MR, MC

To add up several results, use the independent memory M. [M+] adds the current result to M, [M−] subtracts it, [MR] inserts M into the expression, and [MC] resets M to 0.

Example: total power drawn by 100 Ω, 220 Ω and 330 Ω resistors, each connected to 12 V.

1. Press [MC] to clear memory.
2. 12^2/100 → 1.44 → [M+]
3. 12^2/220 → 0.654545454545 → [M+]
4. 12^2/330 → 0.436363636364 → [M+]
5. [MR] → M = 2.53090909091 (W)

Remember the difference: x, y and z overwrite, while M accumulates.

6. Display formats: NORM, SCI, ENG and significant digits

Internally everything is computed in IEEE 754 double precision (roughly 15 to 17 significant digits). The screen rounds to the number of significant digits you choose (6 to 15, default 12).

ENG maps straight onto SI prefixes such as μ (10⁻⁶) and M (10⁶), which is why electronics work favours it. Reducing the displayed digits does not change the stored value; only the display changes, and later calculations keep full precision.

7. Fractions, multiples of π and number bases

• If a result matches a fraction with a denominator up to 10,000 within display precision, the fraction is shown too: 0.75 → 3/4, 1/3 → 0.333333333333 and 1/3.
• Simple multiples of π are shown as well: asin(1) in RAD mode gives 1.57079632679 and π/2.
• Integer results with absolute value up to 2⁵³ also show BIN, OCT and HEX: 255 → 11111111 / 377 / FF.
• You can type bases directly: 0x1F = 31, 0b1011 = 11, 0o17 = 15.

8. Common mistakes

• Forgetting the angle mode. Solve a degree problem in RAD mode and sin(30) returns −0.988. Glance at the DEG/RAD indicator first.
• Not bracketing the denominator. 1/2π is (1/2)×π = 1.5708. For 1/(2π), type 1/(2π) = 0.159155.
• Powers of negative numbers. -2^2 is −4. For (−2)², type (-2)^2.
• Rounding intermediate values by hand and retyping them. Ans and STO keep full precision.

Write the formula in one line, split long work into stored variables, and sanity-check that the answer has a plausible size. Those three habits eliminate most calculator slips.

→ Open the calculator Function Reference

Last updated: 2026-09-24