3又1/2+(-6/7)-40.5+(-1又1/7)

3又1/2+(-6/7)-40.5+(-1又1/7)
3又1/2+(-6/7)-40.5+(-1又1/7)

3又1/2+(-6/7)-40.5+(-1又1/7)
答案是-39.
3又1/2=7/2
-40.5=81/2
-1又1/7=-8/7,
所以上面的题目其实就是=7/2-6/7-81/2-8/7=-74/2-14/7=-37-2=-39