From the makers
Calculator skills
Beginner guide
How to use a scientific calculator
The keypad, SHIFT and ALPHA, brackets, fractions, powers, trig and memory, one worked example at a time.
Calculator skills
How to do fractions on a scientific calculator
Enter fractions and mixed numbers, keep answers exact, and switch to a decimal only when you want one.
Calculator skills
Degrees or radians? Why your calculator says sin 30 = -0.988
The most common trig mistake, how to spot it in two seconds, and when radians are the right choice.
Calculator skills
How to use SHIFT SOLVE on a scientific calculator
Solve an equation for any unknown, why the starting guess matters, and when EQN mode is the better tool.
Explainers
Explainer
6÷2(1+2): is it 1 or 9? Why calculators disagree
Why the internet argues about it, what real calculators do, and how to write it so nobody can misread it.
Investigation
Six tests that expose a broken online calculator
Type sin(180) in degree mode. If the answer is not 0, the calculator is leaking floating point at you.
Calculator guides by topic
Step by step walkthroughs for every mode of the calculator, each with a worked example you can retype key for key. See all 31 guides.
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