计算.①100-98+96-94+92-90+…+8-6+4-2②1001×1001-1001③14+15+16+...
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发布时间:2024-02-24 22:46
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时间:2024-03-03 16:05
①100-98+96-94+92-90+…+8-6+4-2
=(100+96+92+…+4)-(98+94+…+2)
=(100+4)×[(100-4)÷4+1]÷2-(98+2)×[(98-2)÷4+1]÷2,
=104×[96÷4+1]÷2-100×[96÷4+1]÷2,
=104×25÷2-100×25÷2,
=1300-1250,
=50;
②1001×1001-1001
=(1001-1)×1001,
=1000×1001,
=1001000;
③14+15+16+…+45+46
=(14+46)×33÷2,
=60×33÷2,
=990;
④99999×26+33333×22
=33333×3×26+33333×22,
=(3×26+22)×33333,
=(78+22)×33333,
=100×33333,
=3333300.