55乘66加66乘77加77乘88加88乘99的简便计算

分类: 作业答案 • 2021-12-19 18:51:51

问题描述：

答

55×66+66×77+77×88+88×99
=11×5×11×6+11×6×11×7+11×7×11×8+11×8×11×9
=11×11×(5×6+6×7+7×8+8×9)
=121×200
=24200