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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Factorisation and factors

Factorise $3x^2 + 26x + 51$. Hence , find the two factors of $32651$ Workings $$3x^2 + 26x + 51= (x+3)(3x+17) $$ I don't understand how can I use the answer above to help me find factors of $32651$
user307640
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Rounding off figures

A solid block has a mass of 23 grams when corrected to the nearest gram. Find the greatest possible mass of the block . My answer is 23.4kg and I got wrong and the answer is 23.5kg . I was wondering why 23.5 as 23.5 to nearest gram is 24g. Any one…
user307640
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Question about numbers

I have a few questions here that is bothering me a little .. Is '$0$' an even and odd number ? Because $0$ divided by $2$ and $3$ will give you $0$ which is still a whole number Are numbers like $-3 , 7$ called a rational number ? Be fussier can…
user307640
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Factorising large numbers

Can I get some hint for this question, please? I'm told to find the value of $p$ in the following equation $$\dfrac{1}{(2p-1)^4} = \dfrac{1-2p}{32}$$ Here's my thought process ... I can't possibly expand $(2p-1)^4$ as it will make things harder. So…
user307640
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Proportions question

I do not know how to approach this qn properly .. Qn - 6 workers working 8 Hours per day were tasked to complete a building project in 5 days . After working for 3 days , 2 of the workers were sick and could not report to work for the next few…
user307640
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calculating the total amount compunded anually

I invest 10000$ every month for 15 year I want to know how much money I will get after 15 years if I have 10% interest compounded annually.Any formula to find this.Whats the amount i will receive at the end of 15th year including interest?
constantlearner
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Proportion problems

Tension T, newtons , of a string is inversely proportional to the square of the frequency, f Hz , of the note produced . When the tension is 80N , the string produces a note with frequency of 400 Hz . When two identical strings are exerted , the…
user307640
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How to solve 'a÷b(c+d)'?

How to solve $a÷b(c+d)$? For example, $2÷4(8+16)$. Is it $($$\frac{2}{4}$$)(8+16)$ = $\frac{1}{2}$(8+16) = $\frac{1}{2}$(24) = 12? or $\frac{2}{4(8+16)}$ = $\frac{2}{4*24}$ = $\frac{2}{96}$ = $\frac{1}{48}$? Which one is the right one?
User
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Solve this simple problem of Simplification

Simplify $14-\frac{21}{7}+4*2$ Answer given is $3$ but mine is $19$. Where am I doing wrong?
Pranjal Singh
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Possible Typo in Manipulation of Expressions

Someone claimed that the following two expressions are equal. But after much manipulation, I cannot establish their equality. Is there in fact a typo somewhere? $C(x_1^2+x_2^2)^{-(a+p)/2} x_1^p$ $C(x_1)^{-a}(1+x_2/x_1)^{-(a+p)/2}$ I did find that…
J. Sanders
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Formula for monetary amounts with equal taxes

My colleague ran into the following problem while writing billing software. Suppose you have a monetary amount $M$ and a tax rate $t$. For example, $M = 20.1253$ and $t = 0.07$. The question is what are the formulas for the numbers $L$ and $H$…
user141732
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Find the natural number $x$ from this equality. How to solve this type of exercises?

Solve for $x$: $3-\frac{32}{20-\frac{16}{5-\frac{5}{x}} }=1$ When I see exercises like this one I panic because I can't figure out what to do with that variable x. What are the steps in solving an exercise like this one?
alistarmk
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How to derive one percentage from two options

I am very bad at mathematics, so apologies in advance. My confusion comes from the voting system on an online poll. Example video (Picked at random):…
Daniel
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How to prove $r^3+1 = (r+1)(r^2-r+1)$

$r^3+1 = (r+1)(r^2-r+1)$ I know we can simply multiply equations in the right-hand side then we get $r^3+1$. However, is there any way to construct right-hand side without knowing it?
diogenes
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How to calculate participant*hours

I'm trying to calculate the number of "participant*hours" for participation in a program. I have the following variables/data: 1) Total # of sessions given throughout the program. 2) Average duration (in hours) of each session. 3) Average # of…
Lucas
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