KanjiJLPT N3
Gain

gain, get, find, earn, acquire, can, may, able to, profit, advantage, benefit

Mnemonic

At daybreak, a postman slips an ancient measurement stick under your door. Anything you measure with it instantly doubles in value — land, gold, grain. The more you measure, the greater your gain. You measure everything in sight!
Additional thoughts
Picture the golden light of daybreak streaming through the door crack as the postman slides the magical ruler inside. The measurement stick glows each time it touches something, doubling its worth with a shimmer.
Quick recall
A postman delivers a magic measurement stick at daybreak — everything measured doubles in value, an endless gain.

Details

The keyword for 得 is gain. This kanji conveys the idea of acquiring, obtaining, or benefiting from something. It encompasses both the tangible sense of getting or receiving something of value and the more abstract sense of advantage or profit. It can also carry the nuance of being able to do something or finding something possible, linking the concept of gaining ability or opportunity.
On'yomi
とく
Kun'yomi
え.る、う.る