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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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Decimal to days hours

I have $10.73$ and $37.27$ days and I need to convert both to the days:hours format but I'm getting confused mid way. Taking $10.73$ as example I can do $10.73\times24$ to get $257.52$ hours but how do I go about presenting it that 10.73 days is…
wadge
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$n$ = sum of numbers in progression $2^n$

I have looked everywhere and cannot find an answer. If the answer already exists, please refer me to it. I have a number $n$ and need to know the formula to find the numbers in the series $2^n$ that when summed equal $n$. For example: $25 = 16 + 8…
ADGB
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Fast way to manually calculate percentage increments/decrements

I'm currently studying for the GMAT exam, and I'd like to know if there's a way to manually (and quickly) determine an increment/decrement percent between two numbers. I know for example, that if I take 5 as my $100%$ reference value and I then…
Jesús Zazueta
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I need help with percent change and percent difference

I would love if someone were to clear up my confusion. Who is right and what are these things telling me? I'm trying to show the percent change in some software performance times here at work, and I'm having trouble figuring out the math. As I…
Matthew Reddington
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decimal number to another base

There is a formula to convert a decimal number into another base. In below example, we use decimal 255 and we divide it by the base, which could be base 16 or base 2 or another. The first question mark is result of division and the second question…
JohnMerlino
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A number which can be expressed as the sum of the squares of 6 odd integers

Which one of the numbers below can be expressed as the sum of the squares of 6 odd integers? $${1998,1996,2000,2002,2004}$$ I first started this by saying if $m$ is odd then $m = 2k+1$ so $$m^2 = 4k^2+4k+1$$ so $$m^2-1 = 4k(k+1)$$ I'm stuck now and…
Aspiring Mathlete
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Solution to this problem?

Could you solve this question for me? If $10$ years are added to $3/5$ of the age of John, he will be $4$ years younger to the present age of his elder brother who will be $25$ years. What is the present age of John? Thanks in advance.
Karim Ghazali
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Question about something I found in a proof

I came across in a proof I was reading in my textbook that $ab - a'b' = ab - ab' + ab' - a'b'$. I was wondering why/how that equality is true.
user135340
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How to solve equations with modulus in them

For e.g. (100 * X) % 35 = 25 gives X = 2 and on similar note (100 * X) % 360 = 80 gives X = 8 and it can be possible that there is no X which satisfy this for e.g. (100 * X) % 360 = 70 there is no X possible in above case
amitchhajer
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If the sum of $-10.5$ and $+15.0$ is rounded down, it becomes $4$. How to distribute the effect of rounding among the summands?

This may seem a simple stupid question but its driving me crazy for 4 hours. I have two values $-10.5$ and $+15.0$ These values sum $4.5$. For whatever reason that doesn't matter the end result must be floored. The final value in this case must be…
Daniel
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When can $a-(b-c) = (a-b)-c$?

What I'm asking is, when subtracting numbers is there any integers that make $a-(b-c) = (a-b)-c$? Besides $0$ of course. Thanks! Sorry for the stupid question.
user134613
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If I know that $S$ is a square but not its square root, how do I find the next square number?

Given a square number $s = n^2$, is there a way to find the next square $s'$ without knowing $n$? (That is, if you can't take the square root of $s$ to determine $n$, can you compute $s'$?)
James Faulcon
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Finding number $n$ times larger then a given negative number

This is an interesting question, and I can't really answer it. The number which is $5$ times larger than $2$ is $10$ ($2 \times 5 = 10$) But, which number is $5$ times larger then $-2$?
dizarter
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word problem involving interest

Upon entering college, Meagan borrowed the limit of $5000 on her credit card to help pay for expenses. The credit company charges 19.95 % interest compounded continuously. How much will Meagan owe when she graduates in four years ? I wanted to use…
Bob
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(Basic Arithmetic) Multiple number questions: 34 + 54 + 54.

Basic question here but I might aswell get it checked out. I've gone through the multiplication, division, subtraction and addition sections of Khan Academy but something he never went through were multiple number questions like so: 454 + 2324 +…
user2925800
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