اللَّهُمَّ لَا سَهْلَ إِلَّا مَا جَعَلْتَهُ سَهْلًا، وَأَنْتَ تَجْعَلُ الْحَزْنَ إِذَا شِئْتَ سَهْلًا
Allahumma la sahla illa ma ja'altahu sahla, wa anta taj'alul-hazna idha shi'ta sahla
O Allah, there is nothing easy except what You make easy, and You can make what is difficult easy if You will.
Recite when facing a difficult subject or task
This dua acknowledges that true ease comes from Allah alone, and He can make any difficulty easy.