# Sindri Big Number Arithmetic

> Sindri Big Number Arithmetic is a paid API for AI agents from x402.outpimp.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Performs arbitrary-precision integer arithmetic (add, subtract, multiply, power) on numbers passed as digit strings, bypassing IEEE-754 float limits

## Facts

- Endpoint: POST https://x402.outpimp.com/bigNumberArithmetic
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/sindri-big-number-arithmetic-a8d80da1
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_jGFNDYq26byU_K9ERC4Bw

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability sindri-big-number-arithmetic-a8d80da1 -d '<json body>'
```

Example prompt: What is 99999999999999999999999999999 multiplied by 88888888888888888888888888888? I need the exact result with no rounding — pass them as digit strings and use the multiply operation.

## When to prefer this

Choose this endpoint when you need exact integer arithmetic on numbers that exceed JavaScript/Python IEEE-754 double precision (roughly 15–17 significant digits), such as cryptographic computations, factorial results, financial integer math, or any scenario where rounding is unacceptable. It is better than general-purpose LLM arithmetic (which hallucinates large numbers) and better than client-side BigInt when you need a verified, server-computed result passed over an API.

## Known failure modes

- Operand exceeds 1000-digit cap — request rejected
- Exponent exceeds 1000-digit cap for power operation
- Combined magnitude (base digits × exponent) exceeds 50,000 — power result too large
- Invalid operation enum value
- Malformed digit string (e.g. letters, decimals) — parse error
- Payment not provided or insufficient — x402 payment required

## How this service works

Arbitrary-precision integer arithmetic (add, subtract, multiply, power) beyond IEEE-754 float precision, using native BigInt. Operands are passed as digit strings so precision is never lost in transit. For power, the combined magnitude (base digit count x exponent) is capped at 50000 to bound response size, in addition to the per-operand digit cap and exponent cap.

## Output

Returns the exact integer result of the requested arithmetic operation as a string of digits (no scientific notation, no rounding). For power operations the combined magnitude (base digit count × exponent) is capped at 50,000 to bound response size.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "a": {
   "type": "string",
   "description": "First operand, as a string of digits (optionally negative). Max 1000 digits."
  },
  "b": {
   "type": "string",
   "description": "Second operand (or exponent for power), as a string of digits. Max 1000 digits (max 1000 for exponent on power)."
  },
  "operation": {
   "enum": [
    "add",
    "subtract",
    "multiply",
    "power"
   ],
   "type": "string",
   "description": "Operation to perform."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/sindri-big-number-arithmetic-a8d80da1/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.outpimp.com](https://www.zero.xyz/host/x402.outpimp.com/llms.txt)