如题所述
第1个回答 2019-06-04
26×2+26×4+26×6+...+26×50
=26×(2+4+6+...+50)
=26×2×(1+2+3+...+25)
=26×2×[(1+24)+(2+23)+(3+22)+...+(12+13)+25]
=26×2×13×25
=26×650
=16900
=26×(2+4+6+...+50)
=26×2×(1+2+3+...+25)
=26×2×[(1+24)+(2+23)+(3+22)+...+(12+13)+25]
=26×2×13×25
=26×650
=16900
第2个回答 2019-03-05
26ⅹ2+26ⅹ4+26ⅹ6...26ⅹ48+26×50
=26×(2+4+6+......+50)
=26×(2+52)×[(50-2)÷2+1]÷2
=26×54×25÷2
=13×27×2×25
=650×30-650×3
=19500-1950
=19500-2000+50
=17550本回答被网友采纳
=26×(2+4+6+......+50)
=26×(2+52)×[(50-2)÷2+1]÷2
=26×54×25÷2
=13×27×2×25
=650×30-650×3
=19500-1950
=19500-2000+50
=17550本回答被网友采纳
第3个回答 2019-03-05
26ⅹ2 26ⅹ4 26ⅹ6...26ⅹ48 26 50
分别等于52*1 52*2 52*3...52*24 52*25
分别等于52*1 52*2 52*3...52*24 52*25