=SUMPRODUCT(A1:A5,N(OFFSET(B6,-ROW(1:5),)))
两个方法:1、输入=SUMPRODUCT(A1:A5,B1:B5);2、输入=SUM(A1:A5*B1:B5)后按【SHITF+CTRL+回车 】三个键变为数组
=SUMPRODUCT(N(INDIRECT(ADDRESS(6-ROW(1:5),2)))*A1:A5)