After the donation, 3m + m = 132 manual = 33 digital = 99
Before the donation, he had 82 more digital and 26 more manual cameras. 82 + 99 = 181 digital 26 + 33 = 59 manual For a double check, before donation, digital + manual = 240 181 + 59 = 240 So, to begin with, the number of digital cameras = 181.
So, when finding the volume, we would just add up every side, and from the question above, it look like that the numbers that we would be adding are the following above.