小学四年级题目：简算:（76＋49）×5＋81

706

(76＋49）×5＋81
=(75+50)×5+81
=(25×3+25×2)×5+81
=25×5×5+(25×3+6)
=25×25+25×3+6
=25×28+6
=25×4×7+6
=100×7+6
=706

76+49=127
127*5
=130*5-3*5
=(13*5)*10-3*5
=65*10-3*5
=650-3*5
=650-15
=635
635+81=716
答案是716

原式=（76+25+24）×5+81
=（100+25）×5+81
=500+125+81
=625+81
=706

=76*5+49*5+81
=380+245+81
=625+81
=706

:（76＋49）×5＋81
=125×5+81
=625+81
=706