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Hi, please help me with this question.

what is 45+46+47+ ... +53+54?

User Teimurjan
by
8.0k points

2 Answers

3 votes

Answer:

245

Explanation:

1). 91 + 41 + 53 + 54 {Simplify}

2). 138 + 53 + 54 {Simplify}

3). 191 + 54 {Simplify}

4). 245 {Add}

User Fnostro
by
8.1k points
5 votes

9514 1404 393

Answer:

495

Explanation:

There are several ways to figure this:

1) Multiply the average value by the number of numbers. The average number in an arithmetic sequence is the average of the first and last numbers in the sequence.

average = (54+45)/2 = 49.5

number of numbers = 54 -45 +1 = 10

Total = 49.5 · 10 = 495

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2) Add the numbers pairwise. It works best to work toward the middle from the ends:

45 +54 = 99

46 +53 = 99

47 +52 = 99

48 +51 = 99

49 +50 = 99

Total = 5 · 99 = 495

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3) Subtract the sum of numbers to 44 from the sum of numbers to 54.

The sum of numbers 1 to n is (n)(n+1)/2.

(54)(55)/2 -(44)(45)/2 = (27)(55) -(22)(45) = 1485 -990 = 495

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4) Use a spreadsheet or calculator to add them. (see attached)

Hi, please help me with this question. what is 45+46+47+ ... +53+54?-example-1
User Matthijs Steen
by
7.9k points

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