[评论]数学趣题(49): 算式的规律

孤心泪

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21×29 = 618, 2=2,1+9=10: = 1x9+2x(2+1)x100=609
25×25 = 625, 2=2,5+5=10: = 5x5+2x(2+1)x100=625
32×38 = 1216, 3=3,2+8=10: = 2x8+3x(3+1)x100=1216
43×47 = 2014, 4=4,3+7=10: = 3x7+4x(4+1)x100=2021
54×56 = 3024.5=5,4+6=10: = 4x6+5x(5+1)x100=3024


and then
77×73 = ? 7x3+7x8x100=5621
85×85 = ? 5x5+8x9x100=7225
94×96 = ? 4x6+9x10x100=9024
101×109 = ? 1x9+10x11x100=11009
195×195 = ? 5x5+19x20x100=38025
204×206 = ? 4x6+20x21x100=42024

The qualification is the AX*AY, X+Y=10
The result is X*Y+A*(A+1)*100