Question

89+97+92+95+90+94+88+96+87怎么简便计算

Answer 1

89+97+92+95+90+94+88+96+87
=(90-1)+(90+7)+(90+2)+(90+5)+90+(90+4)+(90-2)+(90+6)+(90-3)
=90*9+(-1+7+2+0+4-2+6-3)
=810+13
=823