Any education must be taken together with practice. Bitcoin is precious to practice and if your children make mistakes when making a transaction, bitcoin will be sent to a non exist address, they will lose these bitcoins.

You did not wrote about Test net Bitcoin that is very helpful for practice, for everyone, for you and your children.

Claim Bitcoin Testnet from faucets and use it for practice.
Wiki: https://en.bitcoin.it/wiki/Testnet
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http://bitcoinfaucet.uo1.net/
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