 
<translate> Akwai 80 / 2 = 40 marasa waya da aka sayar. Akwai 80 / 4 = 20 linzamin kwamfuta da aka sayar. Don haka, an sayar da jimillar 40 + 20 = 60 na wayoyin mara waya da na gani. Saboda haka, 80 - 60 = 20 an sayar da berayen trackball a wannan watan. Amsar ita ce 20. <eng> There were 80 / 2 = 40 wireless mice sold. There were 80 / 4 = 20 optical mice sold. So, there were a total of 40 + 20 = 60 wireless and optical mice sold. Therefore, 80 - 60 = 20 trackball mice were sold this month. So the answer is 20. 