Answered

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find the sum : 1+2+3+...+9999+10000


Sagot :

we can assure that there are 10,000 terms by just looking at this. then, use the formula of sum of arithmetic sequence which is S=n/2(first term + last term)
S= 10,000/2(1+10,000)
S=5,000(10,001)
so, S=50,005,000