问题
解答题
1+
|
答案
1+
+1 2
+2 2
+1 2
+1 3
+3 3
+2 3
+…+1 3
+1 10
+…+2 10
+9 10
+10 10
+…+9 10 1 10
=1+
×(1+2+1)+1 2
×(1+2+3+2+1)+1 3
×(1+2+3+4+3+2+1)+…+1 4
×(1+2+3+…+3+2+1)1 10
=1+
×22+1 2
×32+…+1 3
×1021 10
=1+2+3…+10
=(1+10)×10÷2
=55
故答案为:55.