The Cobox — Knowledge is Growth
Tutorials, course notes and interview questions, free for everyone who wants to learn.
- All
- Python 133
- Tools 30
- Tutorials 20
- DATABASE 10
- PHP 8
- C & C++ 5
- Java 4
- Web Development 2
- General Blogs 1
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A 30-day study plan for HTML and CSS
A day-by-day schedule that takes you through the free HTML course (31 lessons) and CSS course (29 lessons) in 30 days, with daily practice, weekly checkpoints and a project at the end of each course.
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How to add a course certificate to LinkedIn and your CV
A practical guide to showing a verifiable course certificate on LinkedIn and on a CV: the Add to LinkedIn button, what to write, where to put it, and how to describe it honestly so it helps.
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PHP certificate: how the final exam and certificate work
How to earn the free PHP course certificate: 54 lessons, a 15-question timed exam drawn from 40 questions, the pass mark, the topics that decide results, and how the certificate is verified.
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MySQL certificate: how the final exam and certificate work
How to earn the free MySQL course certificate: the 50 lessons, the 15-question exam drawn from a 40-question bank, the pass mark, what the questions test, a revision plan and how to verify the certificate.
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CSS certificate: how the final exam and certificate work
How to earn the free CSS course certificate: the 29 lessons, the 15-question timed exam, the 70% pass mark, retries, what to revise for the exam, and how the certificate can be verified.
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HTML certificate: how the final exam and certificate work
Everything about the free HTML course certificate: what you must complete, how the 15-question exam works, the pass mark, retries, what the certificate shows and how anyone can verify it.
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Learn Python with a free video course: how to use the 88 episodes and 21 OOP lectures
How the free Python video course is organised, how many hours it contains, how to study it without drowning, what each stage should leave you able to do, and how it fits with the other courses.
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Learn PHP for free: a 54-lesson course from your first script to a database
What the free PHP course teaches, in what order, how long it takes, what you need to start, and how its lessons, quizzes, final project, exam and certificate fit together.
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Free online tools for developers, writers and everyday life: the complete guide
A guide to all 29 free browser tools on this site, grouped by what you need to do, with what each one is for, when to use it, and why none of them needs an account or uploads your data.
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Numbers in words: lakh, crore, million, and how to write a cheque amount
How the Indian and international number systems name large numbers, how to write rupees and paise in words for cheques and invoices, and how to use the Number to Words Converter.
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BMI explained: formula, WHO and Asian cut-offs, and what BMI cannot tell you
How body mass index is calculated, the WHO categories and the lower cut-offs used for South Asian adults, how to find a healthy weight range for your height, and the limits of BMI.
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Discounts, margin and markup: how to price and how to compare offers
Why stacked discounts do not add up, the difference between margin and markup, how to price for a target margin, and how to use the Discount & Profit Margin Calculator as a shopper or a seller.