Question

69x71 29的简便方法？

69x71＋29的简便方法

Answer 1

69×71+29
=69×（70+1）+29
=69×70+69×1+29
=4830+69+29
=4899+29
=4928

Answer 2

＝69×（70+1）+29 ＝69×70。+70。+29。