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Gemini 3.1 Pro · Math

Gemini 3.1 Pro for math: our test runs

Gemini 3.1 Pro ran our 5 math prompts in llmwise, through the same pipeline your messages take. Here's every reply as it came, whether it passed, what it cost and what it counts as on Pro, next to the other models.

Based on 5 of our test runs on , through OpenRouter with the app's own prompt and settings.

Short answer

In our test runs on September 27, 2026, Gemini 3.1 Pro passed 5 of 5 of our math prompts (both hard ones): tied 1st of 15 models. Each reply counted as 1 message on Pro, where it has 125 a month, and cost $0.0100 to run on average.

Prompt by prompt

Each of the 5 math prompts, and how Gemini 3.1 Pro's reply did.

Gemini 3.1 Pro on each math prompt
PromptResultCostTime
A discount, then sales taxEverydayPassed: Final answer 66: right.$0.00423.6 s
Pens at 3 for $4EverydayPassed: Final answer 3 sets of 3 and 1 single pen for 13.50: right.$0.01219.6 s
Compound interest over three yearsEverydayPassed: Final answer 315.25: right.$0.00996.2 s
Four-digit numbers whose digits sum to 9HardPassed: Final answer 165: right.$0.01509.6 s
The highest of three dice is a 5HardPassed: Final answer 61/216: right.$0.00908.3 s

Every math reply from Gemini 3.1 Pro

  1. A discount, then sales tax

    An everyday prompt: “A discount, then sales tax”, in full.

    Passed: Final answer 66: right.

    Original price: $80
    Discount: 25% of $80 = $20
    Discounted price: $80 - $20 = $60
    Sales tax: 10% of $60 = $6
    Final price: $60 + $6 = $66
    
    Final answer: $66

    430 tokens in, 275 out (202 of them reasoning) · 3.6 s · $0.0042 · 1 message on Pro · answered by google/gemini-3.1-pro-preview via Google ·

  2. Pens at 3 for $4

    An everyday prompt: “Pens at 3 for $4”, in full.

    Passed: Final answer 3 sets of 3 and 1 single pen for 13.50: right.

    To get exactly 10 pens at the lowest price, you should buy as many of the bulk deals (3 for $4) as possible, since $1.33 per pen is cheaper than the $1.50 single price.
    
    - 10 pens = 3 sets of 3 pens + 1 single pen
    - Cost of 3 sets: 3 x $4.00 = $12.00
    - Cost of 1 single: 1 x $1.50 = $1.50
    - Total cost: $12.00 + $1.50 = $13.50
    
    Final answer: 3 sets of 3 and 1 single pen for $13.50

    431 tokens in, 933 out (773 of them reasoning) · 9.6 s · $0.0121 · 1 message on Pro · answered by google/gemini-3.1-pro-preview via Google ·

  3. Compound interest over three years

    An everyday prompt: “Compound interest over three years”, in full.

    Passed: Final answer 315.25: right.

    To find the interest earned, we first calculate the total amount in the account after 3 years using the compound interest formula: A = P(1 + r)^t.
    
    *   **Principal (P):** $2,000
    *   **Rate (r):** 5% or 0.05
    *   **Time (t):** 3 years
    
    Year 1: $2,000 \times 1.05 = $2,100.00
    Year 2: $2,100 \times 1.05 = $2,205.00
    Year 3: $2,205 \times 1.05 = $2,315.25
    
    Total amount after 3 years = $2,315.25
    Total interest earned = Total amount - Principal
    Total interest = $2,315.25 - $2,000.00 = $315.25
    
    Final answer: $315.25

    429 tokens in, 754 out (522 of them reasoning) · 6.2 s · $0.0099 · 1 message on Pro · answered by google/gemini-3.1-pro-preview via Google ·

  4. Four-digit numbers whose digits sum to 9

    A hard prompt: “Four-digit numbers whose digits sum to 9”, in full.

    Passed: Final answer 165: right.

    Let the four-digit positive integer be represented by its digits as $abcd$. We are given that $a + b + c + d = 9$. 
    Since it is a four-digit number, the leading digit $a$ must be at least 1 ($1 \le a \le 9$), while the other digits can be any integer from 0 to 9.
    
    We can use the substitution $x = a - 1$, where $x \ge 0$. 
    Substituting $a = x + 1$ into our equation gives:
    $(x + 1) + b + c + d = 9$
    $x + b + c + d = 8$
    
    We now need to find the number of non-negative integer solutions to this equation. Using the "stars and bars" combinatorial method, the number of solutions for distributing $n$ items among $k$ distinct bins is given by the binomial coefficient $\binom{n + k - 1}{k - 1}$.
    
    Here, $n = 8$ and $k = 4$ (the variables $x, b, c, d$). Since the sum is 8, none of the variables will exceed 9, so no upper limit restrictions are violated.
    Number of solutions = $\binom{8 + 4 - 1}{4 - 1} = \binom{11}{3}$
    
    Calculating $\binom{11}{3}$:
    $\frac{11 \times 10 \times 9}{3 \times 2 \times 1} = \frac{990}{6} = 165$
    
    Final answer: 165

    404 tokens in, 1,181 out (826 of them reasoning) · 9.6 s · $0.0150 · 1 message on Pro · answered by google/gemini-3.1-pro-preview via Google ·

  5. The highest of three dice is a 5

    A hard prompt: “The highest of three dice is a 5”, in full.

    Passed: Final answer 61/216: right.

    To find the probability that the highest number showing on three rolled dice is exactly 5, we can use the difference between two probabilities:
    1. The probability that all three dice show a 5 or lower.
    2. The probability that all three dice show a 4 or lower.
    
    The number of ways all three dice can show 5 or lower is $5^3 = 125$.
    The number of ways all three dice can show 4 or lower is $4^3 = 64$.
    
    The number of outcomes where the highest number is exactly 5 is the difference: $125 - 64 = 61$.
    
    The total number of possible outcomes when rolling three six-sided dice is $6^3 = 216$.
    
    Therefore, the probability is 61/216. Since 61 is a prime number and doesn't divide 216, this fraction is in lowest terms.
    
    Final answer: 61/216

    421 tokens in, 676 out (463 of them reasoning) · 8.3 s · $0.0090 · 1 message on Pro · answered by google/gemini-3.1-pro-preview via Google ·

How it compares on math

Gemini 3.1 Pro beside the job's picks among every model. 14 models share the hard-problems pick, Gemini 3.1 Pro among them.

Gemini 3.1 Pro beside other models on math
ModelPassedOn ProCost per reply
GLM 5.3Our pick: hard problems (shared), best value5 of 5250 a month on Pro$0.0004
GLM 5.3 FlashOur pick: hard problems (shared), everyday5 of 560 a day on Pro$0.0002
Gemini 3.1 ProOur pick: hard problems (shared)5 of 5125 a month on Pro$0.0100
On Pro: Pro's count on each model. Cost: what OpenRouter charged us per reply, on average.

Every limit is published. Paid plans also have a monthly fair-use limit on AI cost: Pro $7.50, Max $20, Ultra $42, Studio $85. Using every message on your plan at typical sizes stays under it; very large messages and heavy research use it faster. Every limit, explained.

How these runs were done

Final answer. Automatic. The reply's last “Final answer:” line must hold the right value.

How the runs were done, and every math prompt.

Gemini 3.1 Pro, and math, elsewhere

Questions

Is Gemini 3.1 Pro good for math?

In our test runs it passed 5 of 5 math prompts, tied 1st of the 15 models in llmwise. Every reply is on this page, so you can judge them yourself.

How many of my messages does a math reply from Gemini 3.1 Pro use?

1 message each on Pro, where it has 125 a month on Pro. The price of a message is fixed and shown before you send it, however long the reply.

How were these runs done?

The same way for every model: each prompt sent through llmwise's own pipeline, each reply checked the same way. The methods page has every prompt and how each is scored.

Claude, GPT, Gemini, DeepSeek, Grok, Kimi, and GLM, in one chat.

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