document.write( "Question 1190794: Find the sum of all-natural numbers from 100 to 300:
\n" ); document.write( "i) Which are exactly divisible by 4.
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Algebra.Com's Answer #822496 by math_helper(2461) $\"\"$ $\"About$

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document.write( "Whenever you have a numbered set of things, the number of elements is the ending number minus the starting number, plus 1:\r
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document.write( "Examples:\r
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document.write( "If we number the elements of {ABCDE} starting from 0, we get:\r
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document.write( "   A    B     C     D     E  
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document.write( "   0    1     2     3     4     --> number of elements = 4-0+1 = 5\r
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document.write( "and if we start at 1:
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document.write( "   A    B     C     D     E
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document.write( "   1    2     3     4     5     -->  number of elements = 5-1+1 = 5
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document.write( "(you see here when you start counting with \"1\" the -1 and +1 always cancel and you can just pick the ending number for this common case)\r
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document.write( "i)  100 maps to 25  (100/4 = 25)
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document.write( "    104 maps to 26
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document.write( "     ...
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document.write( "    300 maps to 75         ---> number of elements of interest = 75-25+1 =  \r
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document.write( "ii)  Here, we are looking for the inverse.   300-100+1 = 201 total elements, and if we take out the 51 found in part (i), we are left with   elements of interest.\r
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