Answer:
 sum is 125,500
sum in summation notation is  = (2a+(n-1)d)n/2
= (2a+(n-1)d)n/2
Step-by-step explanation:
This problem can be solved using concept of arithmetic progression.
The sum of n term terms in arithmetic progression is given by 
sum = (2a+(n-1)d)n/2
where 
a is the first term
d is the common difference of arithmetic progression
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in the problem 
series is multiple of 4 starting from 4 ending at 1000
so series will look like
series: 0,4,8,12,16..................1000
a is first term so
here a is 0
lets find d the common difference 
common difference is given by nth term - (n-1)th term
lets take nth term as 8 
so (n-1)th term = 4
Thus,
d = 8-4 = 4
d  can also be seen 4 intuitively as series is multiple of four.
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let calculate value of n
we have last term as 1000
Nth term can be described 
Nth term = 0+(n-1)d
1000 =   (n-1)4
=> 1000 = 4n -4
=> 1000 + 4= 4n
=> n = 1004/4 = 251
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now we have 
n = 1000
a = 0
d = 4
so we can calculate sum of the series by using formula given above
sum = (2a+(n-1)d)n/2
        = (2*0 + (251-1)4)251/2
        = (250*4)251/2
      = 1000*251/2 = 500*251 = 125,500
Thus, sum is 125,500
sum in summation notation is  = (2a+(n-1)d)n/2
= (2a+(n-1)d)n/2