1) 53*47 = (50+3)*(50-3) = 50^2 - 3^2 = 2500 - 9 = 2491
2) 29.8*30.2 = (30-0.2)*(30+0.2) = 30^2 - 0.2^2 = 90 - 0.04 = 89.96
1) 53*47 = (50+3)*(50-3) = 50^2 - 3^2 = 2500 - 9 = 2491
2) 29.8*30.2 = (30-0.2)*(30+0.2) = 30^2 - 0.2^2 = 90 - 0.04 = 89.96