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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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Strange behaviour in digit sum

I know this is a silly question, but it amazes me and I don't know the explanation. I was driving and jammed in the traffic, and I like to sum in my head the digits on the plate (I'm in Italy, plates contains 3 digits). I noticed this strange…
john
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Ratios of shares

I already asked this question yesterday. I received an answer which was helpful, but I feel like something is still missing. Also I received a -1 and the question get closed for some reason :( So here I come again ... I have to share $100,000$…
Tom Ah
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Computing square roots to specified accuracy

How do I get the square root of a number (3 in this case) that is accurate to a specified number of digits to the right of the decimal point?
Don'tWorry AboutIt
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Why does this work?

Hi I need to know how the equation below works. So I have a number line 0 to 21 each cell is divided into 3 units so 0-2 belongs to first unit, 3-5 belongs to the second unit and so on. This 3 unit cell is further divided into 2 unit cells. So what…
user_1357
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How would I go about finding the weight of something with the square cube law?

I understand that to find the volume you need to multiply width, length, and height. Im just having trouble using that to find weight. So if im doing this correctly. A balck ant weigh around 5 milligrams. Now lets say we increase the size of the any…
Pepper Tee
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What are some applications of extremely large multiple precision arithmetic

I was reading about how people calculate millions, billions, and even trillions of digits of constants like $\pi$. All of these calculations use some implementation of a multiple precision arithmetic library such as GMP (GNU Multiple Precision). I…
Brandon Feder
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How to solve this question on weighted mean?

In one alloy there is 50% steel in its total mass, while in another alloy it is 75%. 15 kg of the first alloy was melted together with 10 kg of the second one to form a third alloy. Find the percentage of steel in the new alloy when it is known that…
Ishrojar Layok
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Should multiplication or division be solved first in this simple interest equation?

I am currently doing a simple interest assignment using the formula $I=PRT$. I have a question where someone is depositing 12500 dollars into their bank and would like to know how long it will take to reach 15000 dollars with a 4.6% interest rate. I…
Demetrius Hiscox
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Speed and distance meeting points an distance travelled

Gemma and Jack live at opposite ends of a street. Gemma had to deliver a parcel to Jack's home, Jack one to Gemma's home. They started their journeys at the same moment and each walked at constant speed, but not necessarily at the same speeds. They…
Harry B
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Distributive law of addition over maximum?

I learned from this article that: For real numbers, addition distributes over the maximum operation, and also over the minimum operation: $a+\max(b, c)=\max(a+b, a+c)$ and $a+\min(b, c)=min(a+b, a+c)$ I wonder if the following distributive law…
Lerner Zhang
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How to find the maximum value involving the sum of positive factors of a number?

$2^{101p}$ and $2^{101q}$ are the factors of $2020^{2020}$. If $s(n)$ denotes all the sum of positive factors of $n$, then find the maximum value of $$4\cdot s\left(2^{p}\right) \cdot s\left(2^q\right)$$. The options: A) $\left(2^{20} -…
user516076
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A long division example in an old book of teach yourself math 1938 wich results in an exact division

Greetings to everyone, Lookin in an old book of the Teach Yourself Series I've found an example which I couldn't understand: Divide $213$ by $39$ the procedure follows like this:(exactly as the book shows) \begin{equation} …
jgrsc
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Summarize a (to me) complicated sales situation with reinvestment of all profits into one neat formula

I'm trying to put the following situation into one simple formula: Imagine a store that sells a product for X. They pay Y for it and profit Z (which may or may not be greater than Y). The store receives the payment A days after the sale. What is the…
InSaNo
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Subtraction of sets

Suppose that I am subtracting the size of two disjoint sets: for instance: $A$ and $B$ as $|A|-|B|.$ The result is presumably an integer. Now, my question is as follows: When I think of subtraction, I think of removing some objects from a given…
Kwame Brown
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Is it not possible to define subtraction in $\mathbb{N}?$as follows...

Can we define subtraction in $\mathbb{N}$ like this: $\forall a,c\in \mathbb{N} (0\notin \mathbb{N})$, $$\exists b\in \mathbb{N}:a+b=c\iff b=c-a$$ I am acquainted with the fact that for $a=2$ and $c=1$ there's no $b\in \mathbb{N}$ such that $2+b=1$…
user923938
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