Using the Diameter Directly in Circumference Questions
You do not have to halve the diameter first unless you want to; C = πd is often the quickest formula.
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Maths notebook
Short explanations for the bits that usually cause mistakes
These posts focus on one question at a time: why a method works, where people commonly go wrong, and how to check the result.
Volume of a Prism: Area of Cross-Section × Length
Every prism volume follows the same idea: find the constant cross-section area, then multiply by the length.
Read the explanation →Finding the Mean from a Frequency Table
Multiply each value by its frequency, add the products, then divide by the total frequency.
Read the explanation →Why Area Uses Square Units and Volume Uses Cubic Units
The powers in cm² and cm³ are not decoration. They tell you how many dimensions are being multiplied together.
Read the explanation →Area or Perimeter? A Simple Way to Tell What the Question Wants
If the question is about covering the inside, think area. If it is about the boundary or distance around, think perimeter.
Read the explanation →Turning a Recurring Decimal into a Fraction
A short algebra trick turns recurring decimals into exact fractions instead of rounded approximations.
Read the explanation →πr² or 2πr? How to Stop Mixing Up the Circle Formulas
πr² measures the space inside a circle. 2πr measures the distance around it. The units give you a quick check.
Read the explanation →Mechanical Keyboard Buying Guide for Work and Home
A non-gaming-first guide to keyboard layouts, switch feel, sound, wireless modes and repairability.
Read the explanation →How to Find a Percentage of a Quantity Mentally
Break awkward percentages into friendly ones such as 10% + 5% or 50% − 1%.
Read the explanation →Noise-Cancelling Headphones: What to Compare Before You Buy
A guide to comfort, active noise cancellation, transparency modes, codec compatibility and travel use.
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