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.

6283 questions
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Basic math question about batches vs totals and remainders

I am struggling helping my little brother with a math question and its a bit embarrassing so I am hoping I can find some help here. We are trying to resolve a problem as follows A total number X should be divided by a known number Y but because it…
Matt Douhan
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Bizarre equation as STQ

I just began filling out a survey for a contest that Walmart is hosting. Since I live in Canada there is a skill testing question which was as follows: $$(4×2)+(6/3)?5=$$ The answer to the equation was omitted. What kind of mathematical significance…
oldboy
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how to obtain specific numbers using some processes on given number?

With a natural number, the following processes can be used: Type 0 at the right of the given number Type number 4 to the right of the given number Divide the number to 2 If number 55 is given, can the following numbers be obtained: 2003, 2004,…
Omar Abu Asbe
  • 99
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Solve in $\mathbb{N}$ the system: $x²-y²=5440$ and $ x \land y = 8$

We have: $$x^{2}-y^{2} = (x-y)(x+y) = 5440 = 2^6\cdot 5\cdot 17$$ $$x \land y = 8.$$ I don't know how to proceed. Thank you for your help.
Zouhair El Yaagoubi
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Prove that $(E): x² - 2px + q = 0 $ if and only if $p² - q \in B \subset \mathbb{Z_{11}} $, and determine $B$.

It is clear that: $x² - 2px + q = (x-p)² - p²+q = 0 $ The equation $(E)$ becomes: $ (x - p)² = p² - q $ Also, we have the equation $x²=a$ admits solutions if and only if $a = 0,1, 4, 9$ (Am I correct?) Which means $(E)$ admits solutions only if…
Zouhair El Yaagoubi
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4 answers

Find 2 variables

Find natural numbers $q, r$ with $0 \leq r < 3$ such that $n = 3q + r$ $n=22$ $n$ is a natural number So I saw there are two unknown variables there and I believe the $0 \leq r < 3$ is the key to solving it but I'm not sure how. Unless I am…
Ace
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Arithmetic Series Proof

Prove : $(a+d)+(a+2d)+(a+3d)+...+(a+nd)=n[\frac{(a+d)+(a+nd)}{2}]$ I have tried proving this by induction but I keep getting stuck at the k+1 step. I have : $k[\frac{(a+d)+(a+kd)}{2}]+(a+(k+1)d)$ which I cannot get to simplify properly. Perhaps I am…
bob
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Difference of two variables, $x$ and $y$

Let's say you have two variables, $x$ and $y$, where $x$ is less than $y$. What would be "the difference of $x$ and $y$"? I think it should be $y - x$, since if you plot them on a number line, $x + (y - x) = y$. But my math teacher says it is $x -…
Ambareesh Shyam Sundar
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Correct usage of %

Wolfram|Alpha evaluates $$2\%\%\%/2$$ to $$1×10^{-6},$$ as well as many other online (google) and offline calculators. My question: Is it really so, and one can represent one millionth as $1\%\%\%$? (Or maybe it is kind of a bug?..) Thank you for…
Oleg Trakhman
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Number of integral values of $\lambda$

From$\lambda cosx> -2$ how they have derived the value of $\lambda$
Koolman
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How many digits does the integer have?

We choose two numbers between $0$ and $9$, and the sum of the numbers should not be $9$. In addition, we cannot choose a number which we have already taken. How many digits does the sum have at most?
maki
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Amount of Rent For Reimbursement

I have a business and I work from home. My accountant says I can reimburse myself for a portion of the rent I pay ($1,500). How can I calculate the money I can reimburse based on the amount of space I occupy while I am working (25 square feet out of…
user424399
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ratio with 3 numbers and 1 unknown

If 6 men dig 9 holes in 10 hrs, how many holes will 10 men dig in 4 hrs if they work at the same rate? We have 6:9:3 and 10:x:4. I formed two equations, $\frac{9}{6}=\frac{x}{10}$ which gives me $x=15$ and $\frac{3}{9}=\frac{4}{x}$ which gives me…
maume
  • 52
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Scale range $[1\times 10^{-12}, 1\times 10^{-6}]$ to $[0-100]$

A method I tried in scaling this range is this common: $(100 - 0) * (x-\min)/(\max - \min)$ If we take $1\times 10^{-9}$ which is somehow in the middle it has to be mapped to $50$ (right?) but it gives me $0.000999$. Anything I'm missing here? Or…
3bdalla
  • 101
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Is there a method of long division where you do it digit by digit, just like long addition/subtraction/multiplication?

Long addition can be done "digit by digit" when you stack the numbers, being sure to carry and align them at their decimal places. Long subtraction can be done digit by digit when you stack the numbers, again aligning them by decimal point and…
DrZ214
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