计算:711/6×6/7+611/5×5/6+511/4×4/5+411/3×3/4+311/2×2/3=_.
问题描述:
计算:71
×1 6
+616 7
×1 5
+515 6
×1 4
+414 5
×1 3
+313 4
×1 2
=______. 2 3
答
:71
×1 6
+616 7
×1 5
+515 6
×1 4
+414 5
×1 3
+313 4
×1 2
,2 3
=(70+
)×7 6
+(60+6 7
)×6 5
+(50+5 6
)×5 4
+(40+4 5
)×4 3
+(30+3 4
)×3 2
,2 3
=60+1+50+1+40+1+30+1+20+1,
=205.
故答案为:205.