Roman Numeral Math

Overview

`roman1` and `roman2` are uppercased and then validated against the canonical pattern for numerals from I to MMMCMXCIX: no symbol repeated more than three times in a row and only the six standard subtractive pairs (IV, IX, XL, XC, CD, CM). Forms such as IIII, IC or VV fail with a 400 that names the bad numeral, so both operands are always between 1 and 3999. Each is converted to an integer by a left-to-right scan that subtracts a smaller symbol placed before a larger one.

`operation` is one of `add` (the default), `subtract`, `multiply` or `divide`, case-insensitive. Division is integer division rounded down and the remainder is discarded, so XX divided by III returns VI. The integer result is then converted back greedily from the largest value down.

Roman numerals have no zero, no negatives and, in standard form, nothing above 3999. A subtraction that comes to zero or less, or a product or sum above 3999, returns a 400 with a message explaining which limit was hit, rather than a partial result.

On success, `result_number` and `result_roman` hold the answer. `equation_numeric` and `equation_roman` write out the whole calculation with the operators +, -, × and ÷, using the numerals as you sent them after uppercasing. `roman1_value` and `roman2_value` are the parsed operands, which is a convenient way to show a learner what each numeral means.

Live Test Roman Numeral Math API →

Endpoint

One host, one path per API. The block below shows this call in four languages; every one of them is the same HTTP request. Making requests covers the timeouts, retries and parameter rules that apply to all of them. The SDKs wrap the same call in a typed client.

1
2

curl "https://api.apiverve.com/v1/romannumeralmath?roman1=XIV&roman2=VI&operation=add" \
  -H "x-api-key: your_api_key_here"

1
2
3
4
5
6
7
8

const res = await fetch('https://api.apiverve.com/v1/romannumeralmath?roman1=XIV&roman2=VI&operation=add', {
  headers: { 'x-api-key': 'your_api_key_here' },
});

if (!res.ok) throw new Error(`${res.status} ${await res.text()}`);

const { data } = await res.json();
console.log(data);

1
2
3
4
5
6
7
8
9
10

import requests

res = requests.get(
    "https://api.apiverve.com/v1/romannumeralmath?roman1=XIV&roman2=VI&operation=add",
    headers={"x-api-key": "your_api_key_here"},
    timeout=15,
)
res.raise_for_status()

print(res.json()["data"])

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21

package main

import (
	"fmt"
	"io"
	"net/http"
)

func main() {
	req, _ := http.NewRequest("GET", "https://api.apiverve.com/v1/romannumeralmath?roman1=XIV&roman2=VI&operation=add", nil)
	req.Header.Set("x-api-key", "your_api_key_here")

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()

	out, _ := io.ReadAll(res.Body)
	fmt.Println(string(out))
}

Replace your_api_key_here with the key from your dashboard. When the inputs arrive as a list rather than one at a time, batch requests run up to 200 of them through this same API in a single call.

Authentication

Send your key in the x-api-key header. That is the only auth step — there is no token exchange and no per-endpoint scope to configure. Authentication covers creating, rotating and revoking keys.

Parameters

Sent in the query string. Premium parameters are accepted on every plan but only take effect on plans that include them.

Response

Every API returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape. Response format covers the envelope, the other output formats and how premium fields are withheld.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15

{
  "status": "ok",
  "error": null,
  "data": {
    "roman1": "XIV",
    "roman2": "VI",
    "roman1_value": 14,
    "roman2_value": 6,
    "operation": "add",
    "result_number": 20,
    "result_roman": "XX",
    "equation_numeric": "14 + 6 = 20",
    "equation_roman": "XIV + VI = XX"
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change. Error handling covers the full status list and which of them are worth retrying.

Use cases

Educational Tools

Teach Roman numeral arithmetic and ancient mathematics in interactive learning applications

Historical Calculators

Create calculators for historical contexts requiring Roman numeral operations

Puzzle Games

Build mathematical puzzles and games using Roman numeral arithmetic

Format Conversion

Perform calculations while maintaining Roman numeral formatting for specialized applications

Other ways to use Roman Numeral Math

Set up Roman Numeral Math on APIVerve, or reach the same source a different way. Your APIVerve account and credits work on all of them — one key, one balance.

Related

More in Math/Calculations: