Hasan Naqvi
Last Activity: 9 Years ago
Only if the no has unit digits as 1,5,6,0 will it be possible for it have the same unit digit again. 0 Won't satify it either, as square of no with 0 in unit digit will have 2 zeros.(like 102=100)
Also, for the square to be a 3 digit no, AB should be smaller than 32.
SO possible options:
15,16,21,25,26,31
Their squares: 225, 256, 441, 625, 676, 961
Only two are of form CCB.
So either AB=15(c=2) or 21(c=4)
So min value = 4+2+1 = 7