How to Solve Math Problems With DeepSeek (and Check the Answer)

The short version

For math, DeepThink is the switch that matters. It makes DeepSeek work through each step before it commits to an answer, and it shows you those steps so you can find a mistake.

Step by step

1. Turn on DeepThink in the message box.
2. Give the whole problem in one message, with every number and unit. If it’s from a textbook, copy it exactly.
3. Say what you want back: the answer only, full working, or hints.
4. Read the reasoning for the step where things went wrong if the answer looks off.
5. Check it. Plug the answer back in, estimate roughly, or ask for a second method.

Prompts to copy

The format DeepSeek recommends:

Please reason step by step, and put your final answer within \boxed{}.
[paste the problem]

The \boxed{} part comes from DeepSeek’s R1 model card. It makes the final answer easy to find in a long reply.

Tutor mode (for students):

I'm a 9th grader learning [topic]. Don't give me the answer.
Give me one hint at a time, and wait for me to try before the next hint.
Problem: [paste]

Check your own work:

Here's my solution to the problem below. Don't solve it from scratch.
Find the first step where I went wrong, if any, and explain why.
Problem: [paste]
My work: [paste]

Everyday math:

I'm comparing two loans: $15,000 at 7.5% for 5 years, or $15,000 at 6.9% for 6 years.
Calculate the monthly payment and total interest for each. Show the formula you used.

Example

You ask (DeepThink on): “A recipe for 4 uses 300 g of flour and 2 eggs. How much do I need for 10 people? Please reason step by step, and put your final answer within \boxed{}.”

A good result: it works out the scale factor (2.5), multiplies (750 g of flour, 5 eggs) and boxes the answer. A quick check: 300 × 2.5 is 750. Correct.

Mistakes to avoid

• Leaving DeepThink off for multi-step problems. The step-by-step reasoning is what you want here, and it lets you see where an answer went wrong.
• Typing an ambiguous expression. “1/2x” could mean 1/(2x) or x/2. Use brackets.
• Not checking the arithmetic. Reasoning models can get the method right and a multiplication wrong.
• Using it to do graded work for you. Check your school’s rules. Tutor mode helps you learn instead.

When not to use it

DeepSeek’s terms say outputs may contain errors and aren’t professional advice. For tax, loan or engineering numbers that carry real consequences, use DeepSeek to understand the method, then confirm with a calculator, the official formula or a professional.

Good to know

If you run a DeepSeek-R1 model locally, its model card also recommends a temperature of 0.5 to 0.7 (0.6 suggested) and no system prompt. See run DeepSeek locally.

Related: use DeepThink and fact-check DeepSeek’s answers.