简便运算99.9x46把 99.9 变成 100-0.1=(100-0.1)x46把括号拆开=100x46-0.1x46=4600-4.6=4595.4得出结果99.9x46=4595.4
99.9×46=（100-0.1）×46=100×46-0.1×46=4600-4.6=4595.4
