Module 1 · What GenAI really is · Lesson 4 of 32
What generative AI can and cannot do
9 minFree GenAI course · BeginnerLesson 1.4By Saket Bhatnagar
Researched and drafted with AI, reviewed and edited by Saket Bhatnagar.
In short
- GenAI is strong at drafting, explaining, summarising, translating and changing the style of things.
- It is weak at fresh facts, exact maths and counting, and at knowing when it is wrong.
- Use it as a fast first draft, then check facts and numbers yourself or with the right tool.
Video lesson · coming soon
What generative AI can and cannot do, in 3 minutes
Lala, your AI mentor, will walk you through this lesson in a short animated video. Until then, everything is here to read and try.
- 01 A perfect Goa plan, with a fake ferry
- 02 The intern who read everything
- 03 Where it shines
- 04 Trust, or verify?
- 05 Flip the myths
- 06 Fast draft, careful check
- 07 Next: tokens, how AI reads
Rohan, a sales executive in Jaipur, asked a chat app to plan a three-day Goa trip for six college friends on a tight budget. In ten seconds he had a lovely plan: beaches by day, a spice farm, a cheap shack for dinner, a packing list and a cost split. Then he checked the ferry it recommended. The timing was wrong, and the shack had closed two years ago.
Both things are true at once. The plan saved Rohan an hour, and parts of it were confidently wrong. Knowing which parts to trust is the most useful skill in this whole course. This lesson gives you that map.
Meet the brilliant new intern
Imagine your office hires an intern named Asha. She has read an astonishing amount: textbooks, novels, manuals, forums, recipes, code. She writes beautifully in many languages and never gets tired. Ask her for a first draft and you get it before your chai cools.
But Asha has a few quirks. She stopped reading the news on a certain date and has not looked since. She does sums in her head and never uses a calculator. And she almost never says “I don’t know”; if she is unsure, she gives her best guess in the same calm voice. Generative AI is a lot like Asha.
Where generative AI shines
Remember from lesson 1 that GenAI creates by following patterns it learned. So it does best when a good answer is mostly about language and patterns, and when “roughly right, then polished by you” is good enough.
- Drafting: a leave application, a cover letter, a reply to a tricky client email, a speech for your parents’ anniversary.
- Explaining: “Explain compound interest like I am fourteen,” then “now with a cricket example.”
- Summarising: a 30-page society meeting PDF turned into five bullet points.
- Changing style: make this message more polite, shorter, more formal, or turn it into Hinglish.
- Translating: a menu or a notice between English, Hindi, Tamil and many other languages, usually well for common languages.
- Brainstorming: twenty names for a home bakery, ten quiz questions for a school fest.
- Coding help: explaining an error, writing a small script, suggesting a fix you then test.
Where it trips up, and why
Each weakness has a plain reason behind it. Once you know the reason, you can predict the mistake before it happens.
Fresh facts
A model only knows what was in its training data, which stops at its knowledge cutoff. Ask about yesterday’s match score, today’s petrol price or a shop that closed last year, and it may answer from old patterns. Many apps now add a web search step to help, but the core model on its own does not know recent events.
Exact maths and counting
A language model writes numbers the way it writes words: by predicting what usually comes next. Small sums often come out right because they appear everywhere in its training text. A long bill split across six friends with GST and a discount is a different story. It can also struggle to count letters in a word, for a reason you will see in the tokens lesson. Good apps hand such work to a calculator or code tool.
Knowing when it is wrong
The model is built to produce text that looks like a good answer. When it lacks the facts, it can still produce something that looks right: a fake book title, a wrong date, a made-up court case. This is called a hallucination, and it has its own lesson in module 2.
Two more limits are worth knowing. The model does not know your private life or your company’s files unless you or the app provide them, which module 4 is all about. And it can repeat biases found in its training data, which module 8 covers.
| Task | How GenAI does | What you should do |
|---|---|---|
| Drafting a polite email | Very well | Read it and adjust the tone to sound like you |
| Summarising a long document you paste in | Well | Spot-check key numbers and names against the original |
| Today’s news, prices or train timings | Unreliable on its own | Check an official source or use an app with search |
| Splitting a ₹14,380 bill with GST | Can slip | Use a calculator, or ask the app to use one |
| Quoting a law, a paper or a book | Risky: may invent sources | Find and open the real source before trusting it |
| Medical, legal or money decisions | Helpful for background only | Talk to a qualified professional |
Should I trust this answer as it is?
Drag to exploreAsk what the task depends on. Language and patterns: trust and review. Fresh facts or exact numbers: verify or use a tool.
Diagram connections:
- Your task to Language or style?
- Your task to Fresh or exact facts?
- Your task to Exact numbers?
- Language or style? to Use it, then review (yes)
- Fresh or exact facts? to Verify or use a tool (yes)
- Exact numbers? to Verify or use a tool (yes)
- Your task: Whatever you asked the AI to do.
- Language or style?: Drafting, rewording, explaining, summarising text you suppl…
- Fresh or exact facts?: Recent events, prices, timings, names, citations.
- Exact numbers?: Totals, splits, percentages, counting.
- Use it, then review: GenAI is strong here; give it a quick read before sending.
- Verify or use a tool: Check an official source, a calculator or an app with searc…
Myths, meet facts
People tend to either overtrust GenAI or dismiss it. Both cost you. Flip these cards to replace six common myths with what is actually true.
Check yourself
Check yourself
Meera wants to use a chat app for four tasks. Where should she be most careful?
Pick an answer to see why it is right or wrong.
Check yourself
Why can a chat app get a long bill split wrong, even though it is a computer?
Pick an answer to see why it is right or wrong.
Remember these three
- GenAI shines at language work: drafting, explaining, summarising, rewording and translating.
- It is weak at fresh facts, exact maths and knowing when it is wrong, and each has a clear reason.
- Use it where checking is quick; verify facts and numbers with sources or tools.
Questions people ask
- What are the main limitations of generative AI?
- It does not know events after its training cutoff, it can state false things confidently (hallucination), and it is unreliable at exact maths and counting. It also does not know your private data unless you provide it, and it can reflect biases from its training data.
- What is generative AI best used for?
- Tasks built on language and patterns, where you can check the result quickly. Think drafting emails and documents, explaining ideas, summarising text you provide, changing tone, translating, brainstorming and helping with code.
- Can I trust facts from AI chat apps?
- Treat them as a helpful starting point, not the final word. For anything important, such as dates, prices, laws, health or citations, confirm it with an official or original source.
- Why is AI bad at maths sometimes?
- A language model produces answers by predicting likely text, not by running arithmetic. Small, common sums are usually fine, but long or unusual calculations can go wrong. Many apps now pass maths to a calculator or code tool to fix this.