加算

1. Origins, structure, and basic meaning

• Structure: 加算(かさん) means adding an amount, score, or quantity to an existing value.
• Basic usage: It describes adding a delivery fee to the base charge.
  • 基本料金に配送料を加算した。

2. Common pitfalls and similar expressions

• Adding generally and adding numerical values
  • 追加(ついか) can mean adding items or tasks. 加算 focuses on numerical addition, as with charges or points.