ichidan verb, intransitive verb
Intransitive: something decreases, lessens, or abates on its own. Slightly formal; in casual speech 減る is more common.
The pain gradually abated.
ichidan verb, transitive verb
Transitive: someone reduces, lessens, or mitigates something. Often used for abstract things like costs, burdens, or risks.
経費を減じる努力が必要だ。
Efforts to reduce expenses are necessary.
リスクを減じる方法を考える。
Think of ways to mitigate the risk.
ichidan verb, transitive verb
Transitive: subtract a number or amount from something. Used in mathematical or financial contexts.
収入から必要経費を減じる。
Deduct necessary expenses from the income.
10から3を減じると7になる。
Subtracting 3 from 10 gives 7.