How to Operate a Scientific Calculator

A scientific calculator does everything a basic calculator does, plus trigonometry, logarithms, exponents, and more - but most of the confusion around using one comes down to just two things: getting the order of operations right, and being in the correct angle mode.

Order of Operations (Why Parentheses Matter)

Scientific calculators evaluate expressions using standard order of operations: parentheses first, then exponents, then multiplication and division, then addition and subtraction. This matters more than it does on a basic calculator because scientific calculators let you type entire expressions - 2 + 3 × 4 correctly gives 14, not 20, because multiplication happens before addition. When in doubt, add parentheses to force the grouping you actually mean.

Degree vs. Radian Mode

Every scientific calculator has a setting - usually labeled DEG and RAD - that controls how trig functions interpret their input. In degree mode, sin(90) equals 1. In radian mode, that same input, 90, is interpreted as 90 radians and gives a completely different result. Whichever unit your problem is stated in, make sure the calculator's mode matches before calculating.

Common Function Keys Explained

• sin, cos, tan - the three basic trigonometric functions.
• asin, acos, atan - their inverses, used to find an angle from a ratio.
• log - base-10 logarithm.
• ln - natural logarithm, base e.
• ^ - exponent, for raising a number to a power.
• π and e - the two most common mathematical constants, built in so you don't have to type their digits out.

A Note on Memory Keys

Many physical scientific calculators also have memory keys - M+, M-, MR, and MC - for storing a running value separately from the main calculation. Since you can type a full expression with parentheses directly into most modern calculators, memory keys are used less often than they used to be, but they're still useful for carrying one intermediate result across several separate calculations.