巧算:12345+23451+34512+45123+51234 怎么办?巧算:12345+23451+34512+45123+51234

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巧算:12345+23451+34512+45123+51234 怎么办?巧算:12345+23451+34512+45123+51234

巧算:12345+23451+34512+45123+51234 怎么办?巧算:12345+23451+34512+45123+51234
巧算:12345+23451+34512+45123+51234 怎么办?
巧算:
12345+23451+34512+45123+51234

巧算:12345+23451+34512+45123+51234 怎么办?巧算:12345+23451+34512+45123+51234
12345+23451+34512+45123+51234
=10000+2000+300+40+5+20000+3000+400+50+1+………………(此处用拆数)
=10000+1000+100+10+1+20000+2000+………………(此处用交换律)
=11111+22222+33333+44444+55555(此处用结合律)
=11111×(1+2+3+4+5)(此处逆用乘法分配律,也就是提取公因数)
=11111×15
=166665