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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Okay I’m stuck and I’m sorry if I sound dumb, I’m new at this. Can anyone help me with 13-79?

I’m trying to figure this out, I’ve tried to look online but everything is the top number is bigger than the small number. I understand what regrouping means and you have to borrow. But I don’t understand 13 - 79 I dont understand. Like do I change…
Stephanie R
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Is it wrong to write $a - x = a + x$ when $x < 0$?

My reasoning would be that since $x$ is negative, $x$ can be rewritten as $-1 \cdot y$ where $y$ is equal to $|x|$. Therefore we can write $a - x$ as $a - (-1) \cdot y = a + y$, which is not equal to $a + x$. I'm asking because it seemed very…
iamtrying
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is it possible to use this trick to convert other things

alright so today I came up with a way to very quickly convert almost any metric value to another first lets say we have 4678 ml and we want to see how many liters that is as we all know its 4.678 but bear with me first I wrote 1000 to represent how…
user10341
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Role of single-valued factors in unitary method

The question here, is very basic in nature but I really can't get the intuition behind it. Consider the following translations:- Degree swept by hour hand in 1 hr:- $12 hr = 360^\circ$ $1 hr = \frac{360^\circ}{12hr} * 1hr = 30^\circ$ Degree swept…
Perspicacious
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Math Question - Find unknown variable with equations

Three-digit numbers P, Q, and R, QQP and PQQ are formed using the single digits P, Q and R such that: PQR + 2 = PQQ and PQR * 2 = QQP Determine all possible combinations of values of P, Q and R that satisfy the two equations. Here is my work so…
HelloWorld1337
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A Cryptarithm Problem from Gelfand's "Algebra"

The following problem is from the very beginning of the book and it even has a solution with explanation. However, I keep banging my head against the wall unable to understand the reasoning behind it. I would be grateful if you could explain his…
blalala
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Number as sum/difference of three squares

I have a puzzling question about this statement : consider four numbers $a,b,c,d \in \Bbb N$, $d\ \notin \Bbb N^2$, is it possible to state that this relation : $d=a^2 + b^2 -c^2$ is always true ? So that it is possible to write that number $d$ in…
Davinator
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How to calculate this number from two others?

Given a number A that increases after a number B has cycled through a range of values (for example, 1 to 4, like below), I'd like to calculate a number C that increases when value B is half way through the cycle. How can I calculate this?
Patrick Hund
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Total Completion Time using Shortest Job First

I am trying to understand the solution of sum of completion times. I found the following stuff in the link: Prompt Scheduling for Selfish Agents Consider the case of a single queue, a selfish agent will simply join the queue immediately upon…
zak100
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Sum of Completion Times

I am trying to understand the solution of sum of completion times. I found the following stuff in the link: Prompt Scheduling for Selfish Agents Paper says: Consider the case of a single queue, a selfish agent will simply join the queue…
zak100
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Fundamental of mathematics

I was wondering what is the concept behind negative numbers? 2x3 is same as 3+3 but when we multiply -2x-3 why is it not the same as -3+-3 ? I am curious behind the reason of this and why do negative numbers behave like this. Thank you!!! have a…
Mr.Farmer john
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How to calculate the modulo using the remainder?

I'm writing an arbitrary-precision arithmetic library. I have methods to calculate the quotient and remainder of a division. I'd now like to add the modulo operator. Modulo and remainder are not the same for negative numbers. How can I calculate the…
BenMorel
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How is Arithmetic different in regards to the definition than the alternative

Good day all, My first post 14 hours ago was an inquiry about how I can develop a solid foundation in understanding and applying mathematics to life. Having got three good responses I've opened up an ages old photo-copied book which I believe will…
Jose Liicks Stuff
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Evaluating $-3(5-7)^2$: multiply by $-3$ or square it first?

As stupid as this is, I don't know. $$-3(5-7)^2$$ Multiply by $-3$ or square it first?
user741357
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Problem related with equation consisting square root

Here's the question I've been thinking for $2$ days and couldn't find an answer why. If $Y = \sqrt{X}$, where both $X$ and $Y$ are real numbers then which of the following is true? a) $X\geq 0$; $Y\geq 0$ b) $X\leq 0$; $Y\geq 0$ c) $X\leq 0$; $Y\leq…
Electrifyings
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