Mathematics Stack Exchange
Mathematics Stack Exchange

Questions tagged [arithmetic]

Questions on basic arithmetic involving numerical quantities only. Questions involving variable values (other than the result of the operation) should be placed under the (algebra-precalculus) tag. Questions about number theory (sometimes called "arithmetic") should not use this tag and should instead use (number-theory) or (elementary-number-theory).

Arithmetic is defined as operations upon numbers using $4$ main operations along with many others:

addition - the sum of two numbers

subtraction - the difference of two numbers also defined as the addition of negative numbers

multiplication - the area of a rectangle with sides of lengths equal to the two operands

division - the number of times one number can be subtracted from another before equaling zero. Sometimes it will allow decimals and in other cases there will be a remainder left over when a number doesn't go into another evenly

See Arithmetic.

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How can I determine the function for summing a series of integers?

I want to sum a series of integers, say from 1 to 5, but I want to generalise this function. I have seen that the function is: $$ \text{sum} = \frac{n(n+1)}{2} $$ where $n$ is the number to sum up to So for $n=5$, i.e. $1 + 2 + 3 + 4 + 5$, the sum…
jcm
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Division with Remainder

When I divide 48/12 by hand, it's 0 Remainder 12. But when I divide it in a calculator, it's .25. Why is this? How does 0R12 turn into .25? Thanks. ANSWER (system won't let me answer my own question because this is my first post) I get it! if you…
Jaji
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Why aren't my % Changes additive?

I'm struggling conceptually with the fact that I have a variable C that is the product of 2 other variables, A and B yet the annual change as a % in C is not the annual change % of A + B. e.g As you can see the total of the 2 is 13.1% not 13.5% -…
Jacob
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How many wins does my team have to get?

I am watching a tournament. 16 teams are participating in the playoff. Every team play against another once. If you win, you score 1 point, if you lose you dont score any point (the outcome of a match can't be draw). To be guaranteed to reach the…
WizardLizard
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SAT Arithmetic Problem

A total of $k$ passengers went on a bus trip. Each of the n buses that were used to transport the passengers could seat a maximum of $x$ passengers. If one bus had $3$ empty seats and the remaining buses were filled, which of the following expresses…
user159778
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Relationship between subsequent squares of integers

Today I realized a relationship between squares of integers that I had not noticed before. If you start with 1, then the squares are 1, 4, 9, 16, 25, 36, 49, 64, 81... The differences between these squares are all odd numbers which keep increasing,…
Harijs Deksnis
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$\forall \ n \in \mathbb{N}: 6\mid 5n^3+n$

Show $\forall \ n \in \mathbb{N}: 6\mid 5n^3+n$ Indeed, we've to show $5n^3+n=0\pmod 6 $ note that for $n\in \{0,1,2,3,4,5\}$ we've: $n^{3}=n\pmod 6$ then $5n^{3}=5n\pmod 6 \implies 5n^{3}+n=6n\pmod 6=0\pmod 6$ AM i right ?
Educ
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Question on Clocks

Three watches are set together. The first gains $5$ minutes a week, the second gains $8$ minutes a week, whilst the third loses $4$ minutes a week. When will they again indicate the same time? Please give me some hint on how to tackle this…
panav2000k
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$AM+GM+HM+RMS=66$

For two reals $a,b\in\mathbb{R}$ Arithmetic mean(AM), Geometric Mean(GM), Harmonic Mean(HM) and Root mean square (RMS) all are integers and $AM+GM+HM+RMS=66$ Find all such $a,b$ I have assumed $a+b=u$ and $ab=v$ and written all the means in the…
Satvik Mashkaria
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how many questions did the answer in each round?

yolanda went on a quiz show. the question in the first round were worth 6 points. the questions in second round were worth 10 points. yolanda answered a total of 5 questions and earned 34 points. how many questions did the answer in each round?
user156866
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I need help with an average question

My brother and I are going on vacation. We need to rent a car. We will rent the car for $10$ days. However, I will only be on the vacation for $5$ days. My brother will be on vacation for the full $10$ days. The cost of the car is $£600$. How much…
PC964
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How to express the relationship between two numbers by dividing?

I recently edited an image to bring it from 194px high to 140px high I'd like to describe how much shorter the image is (or, how different the two are in general) There are two ways to compare the numbers: A) Divide 140/194 to get 0.7216 Which I can…
Drewdavid
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calculating monthly saving rate for 35 years

I have to calculate the monthly value I have to save with 4.5 % interest to get € 529411 in 35 years. As I know, it is about € 520 but I need a formula to integrate it into my software. Thank you
Alexander_F
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How to determine operantors between given numbers to get a given result

In a children's math book I found the following example: There are $2$ numbers: $242, 961$. You can use these numbers as many times as you want, and you can use any arithmetical operator between them. E.g.: $242+242*961-961$ The result must be…
Nestor
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Ratio problem of a beverage

I'm given the following data on a problem: A company wants to produce a beverage AZ which is a mixture of beverage A and Z. Cost/liter of A = 3.00$ Cost/liter of Z = 2.00$ I'm asked to determine the quatities of A and Z required to make 600 liters…
user149031
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