# TypeError: unsupported operand type(s) for +: 'int' and 'str'

**Code:** `TypeError operand` · **Category:** Python · **Seen on:** Python

An operator was used between two incompatible types, such as adding a number to a string.

## Meaning

Python doesn’t convert types implicitly. Values read from input(), files, JSON or environment variables are strings even when they look like numbers.

## Common causes

- input() / env var / CSV value used as a number
- None in arithmetic (NoneType)
- Mixing lists and numbers

## Quick fix

1. Convert explicitly: int(x), float(x), str(x)
2. Use f-strings for text: f"{count} items"
3. Check for None before arithmetic

## Detailed fix by platform

### Python

1. `total = int(qty) * float(price)`

## How to diagnose

1. **Types** — Which two types are named?
2. **Source** — Where does each value come from?

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Source: [WhatIsMyError](https://whatismyerror.com/errors/python/typeerror-unsupported-operand-types-python)