Uchta aralash kasrni qoshish, ayirish, koptirish yoki bolishni hisoblaydi, natijani kasr va onlik son sifatida korsatadi.
Har bir kasr uchun butun son, surat va maxrajni kiriting, ular orasidagi amallarni tanlang va natijani kasr hamda onlik son shaklida oling.
Misol: (1 1/2) + (2/3) x (1 1/4). Kasr 1: butun=1, surat=1, maxraj=2. Qoshishni tanlang. Kasr 2: surat=2, maxraj=3. Koptirish tanlang. Kasr 3: butun=1, surat=1, maxraj=4. Natija: 2 1/6 taxminan 2.167.
