1) 51^2 - 41^2 = (51-41)(51+41) = 10*92 = 920
2) 54^2 - 46^2 = (54-46)(54+46) = 8*100 = 800
3) 76^2 - 24^2 = (76-24)(76+24) = 52*100 = 5200
4) 328^2 - 172^2 = (328-172)(328+172) = 156*500 = 78 000
1) 51^2 - 41^2 = (51-41)(51+41) = 10*92 = 920
2) 54^2 - 46^2 = (54-46)(54+46) = 8*100 = 800
3) 76^2 - 24^2 = (76-24)(76+24) = 52*100 = 5200
4) 328^2 - 172^2 = (328-172)(328+172) = 156*500 = 78 000