计算:1+2+3+…+50+49+…+2+1=______.
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计算:1+2+3+…+50+49+…+2+1=______.
![计算:1+2+3+…+50+49+…+2+1=______.](/uploads/image/z/15429624-24-4.jpg?t=%E8%AE%A1%E7%AE%97%EF%BC%9A1%2B2%2B3%2B%E2%80%A6%2B50%2B49%2B%E2%80%A6%2B2%2B1%3D______%EF%BC%8E)
1+2+3+…+50+49+…+2+1,
=(1+2+3+…48+49+50)×2-50,
=(1+50)×50÷2×2-50,
=51×50÷2×2-50,
=2550-50,
=2500.
故答案为:2500.
=(1+2+3+…48+49+50)×2-50,
=(1+50)×50÷2×2-50,
=51×50÷2×2-50,
=2550-50,
=2500.
故答案为:2500.
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