这个可以实现
=LOOKUP(A1,{1,4,7},{"小","中","大"})
或
=IF(A1<4,"小",IF(A1<7,"中","大"))
公式=LOOKUP(A1,{1,4,7},{"小","中","大"})
=lookup(A1,{1,"小";4,"中";7,"大"})