How Do You Enter Answers and Use the Virtual Calculator in GATE?

October 25, 2026•Last verified October 29, 2026•8 min read

In GATE you answer on screen and calculate on screen. MCQ and MSQ answers are chosen from four options, NAT answers are typed on a virtual keypad with the computer keyboard switched off, and the only calculator is a virtual scientific calculator on the monitor. This post sets out exactly what the official GATE 2027 documents from IIT Madras say about each, what they don't say, and the habits that keep a correct method from turning into a wrong NAT answer.

Practise on the official calculator first

The GATE 2027 brochure (section 7) says mock examination links "together with the virtual scientific calculator will be accessible through GATE 2027 official website". As of 27 October 2026 they aren't posted yet, so check the GATE 2027 website. Until they are, practise on the official virtual scientific calculator page hosted by TCS iON, and on the GATE 2026 mock tests, linked from IIT Guwahati's GATE 2026 site "to help GATE 2026 candidates familiarise themselves with the look and feel" of the test. For extra practice with a mouse or a tap, our unofficial practice calculator has the same keys in the same order, with ten GATE EC exercises.

Official mock tests and practice

How MCQ, MSQ and NAT answers are entered

MCQ (brochure section 7.2.1): four choices, of which only one is correct. You select one. A wrong answer costs 1/3 mark on a 1-mark question and 2/3 mark on a 2-mark question.
MSQ: four choices, of which one or more are correct. You get the marks only if you select exactly the correct combination. There is no negative marking and no partial marking.
NAT: no choices are shown. The answer is a signed real number, "which must be entered by the candidate using the virtual numeric keypad on the monitor (keyboard of the computer will be disabled)". There is no negative marking and no partial marking.

How a NAT value is typed

The brochure gives the forms a NAT answer can take: an integer such as 10 or -10, or a decimal such as 10.1 (one decimal), 10.01 (two decimals) or -10.001 (three decimals). So answers can be negative, and you enter the sign on the keypad along with the digits. The question itself says how many decimal places to give: "The stem or main body of the NAT question will indicate the number of decimal places that must be specified in the answer." The brochure's own example ends with "(rounded off to two decimal places)". It doesn't describe the keypad's layout, so look at it in the official mock test before the exam.

Rounding: once, at the end

The brochure advises candidates "to round-off only at the end of the calculation and not at intermediate stages of the calculation". A small example shows why. Add 2/3 three times. At full precision the total is exactly 2, which is 2.00 to two decimal places. Round each 2/3 to 0.67 first and the total is 2.01, a different answer from a correct method. Keep the full value on the calculator until the last step, then round once to the number of decimal places the question asks for.

What the official documents say about the calculator

It is on the screen: "A virtual scientific calculator will be available on the computer screen" (brochure, section 7).
It is the only one: "The candidates must use only the on-screen virtual calculator provided for their calculations" (brochure, section 2, highlights). The FAQs add that every candidate is given it and that it "has to be used to answer the questions".
A physical calculator means disqualification: calculators, phones and watches of any kind are prohibited in the hall, and candidates found with them "will be disqualified regardless of whether they use them or not" (section 7). The FAQs say the same of a calculator built into an electronic watch.
It will be on the official website with the mock tests (section 7), as above.

Every key on the official calculator

Arithmetic: +, −, ×, ÷, mod, % (two numbers: a % b is b percent of a), brackets, ± (change sign) and |x| (absolute value).
Powers and roots: x², x³, xʸ, 1/x, √, ∛ (cube root), ʸ√x (y-th root: x first, then ʸ√x, then y, so 8 ʸ√x 3 = 2), 10ˣ, eˣ, and Exp for powers of ten.
Logs: log (base 10), ln, log₂x and logᵧx (any base: the number first, then logᵧx, then the base, so 8 logᵧx 2 = 3).
Trigonometry: sin, cos, tan and their inverses, with Deg (selected at the start) or Rad.
Hyperbolic: sinh, cosh, tanh and their inverses.
Constants and factorial: π, e and n!.
Memory: MC, MR, MS, M+ and M−. Editing: backspace, C and =.
There are two display lines: the expression on top and the result below.

Number first, then the function

The calculator works out 2 + 3 × 4 = as 14, with the usual order of operations, so you can type a sum the way it is written. Functions are different: you type the number first, then press the function. To get sin 30, type 30, then press sin; pressing sin first and then 30 is the slip to avoid. A function acts on the number just typed, so for log of a sum, bracket the sum first and press log after closing the bracket. Press the function before =, not after it: type the number, then the function, then =. In one check on the official calculator, π ÷ 3 = followed by cos in Rad left π/3 itself on the display, so cos was not applied to the result.

What the official Help screen says

The official calculator has a Help screen. This is its text, quoted word for word from the Help screen of the official GATE virtual scientific calculator (TCS iON), spelling as shown there. It is headed “Calculator Instructions” and begins: “Allows you to perform basic and complex mathematical operations such as modulus, square root, cube root, trigonometric, exponential, logarithmic, hyperbolic functions, etc.” “You can operate the calculator using the buttons provided on screen with your mouse.”

Do's: “Be sure to press [C] when beginning a new calculation.”
Do's: “Simply an equation using parenthesis and other mathematical operators.”
Do's: “Use the predefined operations such as p (Pi), log, Exp to save time during calculation.”
Do's: “Use memory function for calculating cumulative totals.” “[M+]: Will add displayed value to memory.” “[MR]: Will recall the value stored in memory.” “[M-]: Subtracts the displayed value from memory.”
Do's: “Be sure select the angle unit (Deg or Rad) before beginning any calculation.” “Note: By default angle unit is set as Degree”
Dont's: “Perform multiple operations together.”
Dont's: “Leave parenthesis unbalanced.”
Dont's: “Change the angle unit (Deg or Rad) while performing a calculation..”
Limitations: “Keyboard operation is disabled.”
Limitations: “The output for a Factorial calculation is precise up to 14 digits.”
Limitations: “The output for Logarithmic and Hyperbolic calculations is precise up to 5 digits.”
Limitations: “Modulus (mod) operation performed on decimal numbers with 15 digits would not be precise.” “Use mod operation only if the number comprises of less than 15 digits i.e. mod operation provides best results for smaller numbers.”
Limitations: “The range of value supported by the calculator is 10(-323) to 10(308).”

What this means for you

Mouse only: the keyboard doesn't work on the calculator, so practise clicking or tapping the keys.
Press C before each new calculation, so nothing is left over from the last one.
Check Deg or Rad before you start: Deg is selected at the start, and the angle unit shouldn't be changed partway through a calculation.
Log and hyperbolic results are precise only up to 5 digits. Be careful when a NAT answer needs more, or when you subtract two logs of nearly equal numbers: divide first and take one log instead, as in the practice calculator's exercise.
There is no way to enter a negative exponent with Exp: type small values directly (0.002) or divide (2 ÷ 1000).
% binds tighter than + and −: 200 + 10 % 10 = works out 10 % 10 = 1 first and gives 201.
The supported range is 10⁻³²³ to 10³⁰⁸, far wider than any GATE answer needs.

Exp means times ten to the power

Exp enters a power of ten as part of the number: 2 Exp 3 = gives 2000, and 3 Exp 8 is 3 × 10⁸, the speed of light in m/s, as one number. Because it is one number, 3 Exp 8 ÷ 1.5 Exp 6 = should give 200 with no brackets, as it does on our practice calculator. Typing × 10 xʸ 8 instead is more key presses and easier to get wrong.

Watch out: there is no negative exponent with Exp

% takes two numbers

The % key works between two numbers: a % b gives b percent of a, so 50 % 50 = gives 25, and 200 % 15 = gives 30. Pressing 50 % = on its own gives 50, not 0.5, so don't use % to divide by 100. Inside a sum, % binds tighter than + and −: 200 + 10 % 10 = works out 10 % 10 = 1 first, then gives 201.

What the display shows

Plain arithmetic is shown at full precision: 2 ÷ 3 = gives 0.6666666666666666. Function results are cleaned of the tiny floating-point errors a computer makes: 30 sin gives 0.5, not 0.49999999999999994, and 81 logᵧx 3 = gives 4. Very large results switch to e-notation, so 10 xʸ 21 = shows 1e+21. Either way, keep the full value until the last step and round once, to the decimal places the question asks for.

No nCr and no complex numbers

The calculator has n! but no nCr key, and no complex-number mode. For combinations, use n! ÷ (r! × (n − r)!), keeping the bracket round the bottom line: 6! ÷ (2! × 4!) is 15, but 6! ÷ 2! × 4! is 8640. For complex numbers, work with the real and imaginary parts separately: the magnitude of 3 + j4 is √(3² + 4²) = 5 and its angle is tan⁻¹(4/3), or do the algebra by hand on the scribble pad.

Still to check on the real one

We haven't confirmed these on the official calculator, so try them there before you rely on them: whether a result can be copied into the NAT answer box or must be typed on the keypad; exactly how many decimals it shows for function results such as 2 log or 40 sin; what ± or − straight after Exp does for other numbers, since 2 Exp ± 3 = gives 197 but 5 Exp ± 2 = gives 500; what a function key does straight after =; and when it switches to scientific notation for very small results.

Habits that save NAT marks

Degrees or radians: Deg is selected at the start. If the angle has π in it, it is in radians, so press Rad first. A degree-mode cos(π/3) is not 0.5.
Number before function, and both before =: type 30, then sin, then =. For a function of a sum, close the bracket first, then press the function.
Brackets: the calculator follows the usual order of operations, but bracket every numerator and denominator with more than one term anyway.
Keep full precision: store intermediate results with MS and recall them with MR instead of copying a rounded value by hand.
Powers of ten: use Exp, so 4.7 Exp 3 is 4700 as one number. Never press ± or − after Exp: for negative powers, type the value directly or divide, 4.7 ÷ 1000.
Units before rounding: if the answer is asked in ms or dB, convert first, then round. 0.003257 s is 3.26 ms to two decimals.
Decibels: 10 log for power ratios, 20 log for voltage or current ratios.
Precision: give exactly the decimal places the stem asks for, and remember the sign for a negative answer.

Working by hand: the scribble pad

Rough work goes on a scribble pad provided at the centre (section 7 and Appendix C). You can hold only one pad at a time: hand the first back to the invigilator before you take a second. Write your name and registration number on it before you use it, and return every pad before you leave the hall. Algebra and set-up go on the pad; the arithmetic that needs a calculator goes on the screen.

Go deeper

Official sources

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Sources and last verified date

Every GATE 2027 fact in this post was checked against the official GATE 2027 information brochure (sections 2, 7 and 7.2.1), FAQs and website from IIT Madras, and the GATE 2026 mock test page from IIT Guwahati, on 27 October 2026. The calculator's keys, its default angle mode, its order of operations, number-then-function input, Exp (including ± and − after it), % (including inside a sum) and logᵧx were checked on the official virtual scientific calculator on 27 and 28 October 2026, as were its full-precision results (2 ÷ 3 = gives 0.6666666666666666) and its Help screen, quoted above. Its noise-free function results (30 sin gives 0.5, 81 logᵧx 3 = gives 4), ʸ√x order, 5 Exp ± 2 = giving 500 and 10 xʸ 21 = showing 1e+21 were checked on 29 October 2026. Official rules can change, so confirm anything you plan around on the official site. Studyloaf is not affiliated with GATE, any IIT or TCS iON.