1×2+2×3+…+100×101=_.
问题描述:
1×2+2×3+…+100×101=______.
答
1×2+2×3+3×4+…+100×101
=(12+1)+(22+2)+(32+3)+…+(1002+100)
=(12+22+32+…+1002)+(1+2+3+…+100)
=
+100(100+1)(2×100+1) 6
100×(100+1) 2
=338350+5050
=343400
故答案为:343400.