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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Question about finding cube root by hand

To find the square root of $125$ by hand: $$ \begin{array}{l|l} & 1,25.00 & 11.1 \\ &1 & \\ \hline 21 & \space \space \space \space 25 & \\ &\space \space \space \space21 & \\ \hline 221& \space \space \space \space \space \space 4.00&…
ronald christenkkson
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Order of operations for solving for x

What is the order of operations for solving any variable? I assumed it was the opposite of PEMDAS, but in $2x^2 = 4$, you have to deal with the exponent first before dividing out to get a correct answer which breaks the order. Unlike $5^{(2x^2-1)} =…
Haridasa
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Is there a mathematical way to solve this rounding issue

Background: I have a backend system that only accepts prices at an 'each' level with 2 decimal places. IOW you can send a price of 2.99 into the system for an order. But we want to offer dollar off discounts (i.e. $10 off when you spend over 100).…
JM Gold
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Three of four numbers have a sum of $22$. If the average of the four numbers is $8$, what is the fourth number?

For some reason I'm drawing blanks on how to solve this type of question. You have $3$ of $4$ numbers that have a sum of $22$. The average of the $4$ numbers is $8$, so what's the formula for solving for the $4^{th}$ number?
Justin
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Why do we use division to find the value of 1 item?

If 4 apples is 16 dollars them 1 apple is 16÷4 dollars? Why do we use division here? What does it mean? If a car goes 60meter in 60 seconds,it goes 60÷60 m in 1s. How does that work? Why division and why not other operators like subtraction? How…
Soha
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Formula to figure out who owes who how much money for shared expenses

I feel like this is a super basic math problem but I've had a long day and it's stumping me. Two people are paying for some shared expenses. Some expenses are private. Some expenses are not shared and one person owes the other. I'm trying to come up…
IMTheNachoMan
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Problems with percentages

Let's say there's a fee of 5% applied on funds deposit - how much do I have to deposit in order to have net $\$100$ in an account? I thought it's simply $\$105$ :D (however then fee = 5,25).
lol
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In and out to reach the same volume in boxes

Good day! Can someone help me with a math problem? Boxes X, Y, and Z contain 14.7 liters of water in total. 2/7 of the water in Box X is poured into Box Y. Then, 1/3 of the water in Box Y is poured into Box Z. After that, the volume of water in…
Mark K
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Calculating recurring revenue for period of time

I am trying to figure out the best formula for calculating recurring revenue over a period of time. For example: I charge $10 a month for a subscription services. Every month I get an extra client. What is the simplest formula for calculating this…
ipengineer
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Can Arithmetic Mean >= Geometric Mean be applied in this way

Find the minimum value of the sum of real numbers a^(-5), a^(-4), 3*a^(-3), 1, a^8 and a^10 when a>0. ignoring 1 for now, as it can be added later We can find the solution by breaking 3*a^(-3) into a^(-3),a^(-3),a^(-3) and then applying Arithmetic…
codeactor
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Do Idoneal numbers give infinitely many primes?

Euler famously showed that there are at least 65 idoneal (convenient) numbers. This was Euler's definition of idoneal number: The number $n$ is idoneal if the following holds: Let $m>1$ be an odd number relatively prime to n which can be written in…
francois
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Fractions and linearity

Imagine that the price of a good is given as $5$/unit. Mathematically, if we are to compute how much we can buy with 1\$, this would just be 1\$/5\$ per unit=0.2 units. However, this computation relies on ``linearity''. In other words, we can…
Kwame Brown
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Help understanding how to Evaluate divisions

Morning to everyone, I am trying to understand a problem I came across, which I can solve but I still do not understand the logic behind it. The problem is as follow Input: equations = [["a","b"],["b","c"]], values = [2.0,3.0], queries =…
Sgr
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If $ABCDE\times4 = EDCBA$ where $A, B, C, D, E$ are all distinct. Why can't $E$ be $3$?

If $ABCDE\times4 = EDCBA$. Here $A, B, C, D, E$ represent distinct nonzero digits and $ABCDE$ and $EDCBA$ are five digit numbers. Why can't E be three?
user1202451
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Long divison and calculator answers totally differ

So I've looked around and no one seems to have an answer for this. 12/150 = 12 remainder of 6 by long divison. Yet calculator and Google both say answer is 0.08. What am I missing and how did this get calculated??
Soolost
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