換える

1. Origins, structure, and basic meaning

• Structure: 換える is read as かえる and can mean “to change” or “to exchange”, depending on context.
• Basic usage: The examples show replacing stale room air and exchanging a banknote for coins.

2. Common pitfalls and similar expressions

• Distinguishing senses and uses
  • This spelling is used for exchanging or replacing with an equivalent function or value; general alteration is often 変える.