Guides
The reasoning behind the buttons: why the order of operations is fixed, what a logarithm is asking, and how much precision an answer should carry.
Order of Operations
The fixed sequence every calculator follows, and the two rules people miss.
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Fractions, Decimals and Percentages
Three notations for the same quantity, and how to move between them.
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Logarithms
One question, asked backwards: what power produced this number.
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Rounding and Significant Figures
How precise to be, and how to avoid losing marks getting there.
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Why These Four
They are the topics where a confident wrong answer is most likely. Order of operations decides what an expression even means. Fractions, decimals and percentages are one idea in three notations that questions deliberately mix. Logarithms look harder than they are until you read them as a question about exponents. Rounding quietly loses marks at the very last step.
Each guide is written to be read once and remembered, not skimmed. If you want to use the ideas straight away, the tools apply them, and the blog covers working accurately under time pressure.