199+299+399+499+599+…+9799+9899=______.-数学

题目简介

199+299+399+499+599+…+9799+9899=______.-数学

题目详情

1
99
+
2
99
+
3
99
+
4
99
+
5
99
+…+
97
99
+
98
99
=______.
题型:填空题难度:偏易来源:不详

答案

class="stub"1
99
+class="stub"2
99
+class="stub"3
99
+class="stub"4
99
+class="stub"5
99
+…+class="stub"97
99
+class="stub"98
99

=
(1+98)×98÷2
99

=class="stub"99×98÷2
99

=98÷2,
=49.
故答案为:49.

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