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I need a Math Whizz.

N

Northern Rancher

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Feb 10, 2005
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saskatchewan
Find the sum of the integers between 12 and 417 which are multiples of 7.

The answer is 12,383. I don't know the equation to come up with the answer though.

No fair that Dad's have to help with highschool algebra lol.
 
Ai Carumba!!!

The teacher last year, I had to have her formulas, and not the one that made sence to me, so I got a 25 on my report card, cause I got them all right, but I lost three marks for not using her formula. The teacher will check your work now, and will explain all the ways of doing it. as long as yo get the right answer, shes happy.
 
The smallest and largest numbers between 12 and 417 which are divisible by 7 are 14 and 413.

There are 58 numbers between 14 and 413 which are divisible by 7 the smalles is 2, the largest is 59

If you take the average of 14 and 413 you get 213.50.

Multiply 58 times 213.5 and you get 12,383

You can check it real quick with a spreadsheet
 
The smallest and largest numbers between 12 and 417 which are divisible by 7 are 14 and 413.

There are 58 numbers between 14 and 413 which are divisible by 7 the smalles is 2, the largest is 59

If you take the average of 14 and 413 you get 213.50.

Multiply 58 times 213.5 and you get 12,383

You can check it real quick with a spreadsheet
Click to expand...

[(14+413)/2]*58=12383

*-multiplication
 
NR. If this isn't correct or need more help.. #1 said that the sample equasion in the book would be of great help....
Sorry so late on the reply...... We moved cows to corn stalks and hauled manure till real late yeaterday.......
 
I think y'all are barking up the wrong tree but I don't have the book I need with me right now to look it up to be sure.
It has been a very long time but I am thinking of a mathematic tool call a factorial. If I remember correct, the symbol looked sort of like an exclamation mark. I am not at all sure that remember how to use it and I don't have calculator with it on it right now but I am thinking that the easy way to solve your problem would be:
7 factorial 417 – 7 factorial 12 or something like that.
I will look it up in a day or two and get back with you.
 
alabama said:
I think y'all are barking up the wrong tree but I don't have the book I need with me right now to look it up to be sure.
It has been a very long time but I am thinking of a mathematic tool call a factorial. If I remember correct, the symbol looked sort of like an exclamation mark. I am not at all sure that remember how to use it and I don't have calculator with it on it right now but I am thinking that the easy way to solve your problem would be:
7 factorial 417 – 7 factorial 12 or something like that.
I will look it up in a day or two and get back with you.
Click to expand...

Boy was I ever wrong. I way missed the meaning of factorial. Dang I must be getting way too old.
Well anyway the following is a Factorial and is no help in the original question. LOL

The factorial "n!" is defined for a positive integer as

n! = n(n-1) ...2*1

So, for example, 4! = 4*3*2*1 = 24
(Mellin 1909; Lewin 1958, p. 19; Dudeney 1970; Gardner 1978; Conway and Guy 1996).
 

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