(111+121+131+141)×(121+131+141+151)−(111+121+131+141+151)× (121+131+141)．
问题描述：
(
+1 11
+1 21
+1 31
)×(1 41
+1 21
+1 31
+1 41
)−(1 51
+1 11
+1 21
+1 31
+1 41
)× (1 51
+1 21
+1 31
)． 1 41
答
答案解析：因为数值较大，令111+121+131+141=a，121+131+141=b，然后用字母进行表示，然后再进行计算即可．
考试点：分数的巧算．
知识点：本题运用字母表示出较长的算式，便于计算书写．