Explain Variables and Data Types Like I'm 12

You started learning to code and the tutorials explaining variables somehow assume you already know what a variable is. This explains it as you would to a sharp twelve-year-old: what a variable is and why you bother, the difference between strings, integers, floats, and booleans, and why types matter. Real-world analogies, zero jargon.

I just started learning {LANGUAGE} and I keep hearing about variables and data types but the tutorials I've read feel too technical.

Please explain these concepts in plain everyday language, as if talking to a curious 12-year-old. Use real-world analogies, not programming jargon, to describe:
- What a variable is and why we use one
- The difference between a string, integer, float, and boolean
- Why data types matter and what goes wrong when you use the wrong one
- How to declare a variable in {LANGUAGE} with a simple example

After your explanation, give me three short practice exercises I can do right now in under 10 minutes to test my understanding, with expected outputs so I can check myself.