1-5/12+4/15+1/12-14/15-39/20=?
问题描述:
1-5/12+4/15+1/12-14/15-39/20=?
答
1-5/12+4/15+1/12-14/15-39/20
=1-4/12-10/15-39/20
=1-1/3-2/3-39/20
=-39/20