6999999+699999+69999+6999+699+69的简便综合算法是什么?
问题描述:
6999999+699999+69999+6999+699+69的简便综合算法是什么?
答
6999999+699999+69999+6999+699+69
=7000000-1+700000-1+70000-1+7000-1+700-1+70-1
=7777770-6
=7777764