# Multiply decimals exactly from an AI agent

You need the product of two decimal amounts, such as a price times a quantity, without binary floating-point error and with a stated rounding rule.

**Use `decimal-multiply@1.0.0`.** It is free and needs no key or sign-up. Multiply two decimal strings exactly, optionally rounding the product once to a fixed scale with a chosen mode.

## Why call a tool for this

Numbers travel as strings and stay exact. The result says whether rounding happened, so the agent can report it.

## Call it over HTTP

```sh
curl -X POST https://computefirst.net/v1/tools/decimal-multiply/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"a":"19.99","b":"3"}'
```

Response:

```json
{
  "result": {
    "value": "59.97",
    "exact": true
  }
}
```

## Call it over MCP

Connect `https://computefirst.net/mcp` ([setup](/docs#connect)), then call `execute` with:

```json
{
  "id": "decimal-multiply",
  "version": "1.0.0",
  "input": {
    "a": "19.99",
    "b": "3"
  }
}
```

## Check the result

The tool multiplies exactly two factors, passed as strings. Leave out scale and rounding for the exact product. If your task defines a rounding rule, set both together, and read the exact field in the response.

Full contract, limits and unsupported cases: [Decimal multiply](/tools/decimal-multiply).

## Related tools

- [Decimal add](/tools/decimal-add)
- [Money minor units convert](/tools/money-minor-units-convert)