Chain of thought — CCA-F Exam Prep

L2.03|Chain of thought

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Try this yourself

A chat interface showing a math word problem. Claude's response is a single number, wrong, highlighted in red. Below: the same prompt with 'Think step by step' appended. Claude's response shows detailed reasoning and the correct answer highlighted in green.

You ask Claude a word problem. It answers instantly. Confidently. Wrong.

"A store sells notebooks for $4 each. If you buy 3 or more, you get 25% off the total. Tax is 8%. How much do you pay for 5 notebooks?"

Without chain of thought, Claude often jumps to an answer: "$16.20." Sounds plausible. It's wrong. The correct answer is $16.20... wait, that IS right sometimes. The point is Claude doesn't show how it got there, so you can't verify it. And on harder problems, the jump-to-answer approach fails badly.

Now add five words to the end of your prompt: "Think through this step by step."

Claude writes out each calculation. 5 x $4 = $20. 25% off = $15. 8% tax = $1.20. Total: $16.20. Verifiable. Correct.