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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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Why digit sum of 841 is 4 instead of 13?

So I've just bought an app from the playstore. It's a mental math app. I need it for my new job that require me to do calculation out of paper. Have a look at the forth step shown in the image. Why so? Also, how it chooses 29 ( I know the process…
Plain_Dude_Sleeping_Alone
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problem with pupils and find the number of the pupils -arithmetic

In a classroom there are 28 pupils. 19 pupils know to speak English ad 16 pupils speak French. Knowing that every children is speaking at least one language(English or French) find out the number of pupils who are speaking only English. Thanks:)
Iuli
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Is it posible to multiply 2 rational numbers by using only addition/subtraction?

Let $a,b\in\mathbb{Q}$ How can I do the operation $a*b$ without knowing multiplication tables and without the help of a calculator? (Well, is it posible?) If only one of them were whole numbers, it would be really easy: If $a\in\mathbb{Z}$ just…
Victor Oliva
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Calculator evaluating expressions erroneously?

Could you please explain to me why the answer of the equation $(24+3) - \frac{27}{3} \times 5$ is $-18$? How come it was negative when in my calculator it's postive? Also this equation too, with a modulo problem: $12 \times 2 \div 3 \, \% \times…
hooely
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A question about orders of magnitude

I'm reading a book in which the author compares two pairs of numbers $(0.31, 0.39)$ and $(6.10,0.39)$ and multiplies the second member of each pair by a factor $R_1 = 2$ and $R_2 = 20$ so that both members of the pair "have the same order of…
Olumide
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Formula for offsetting some additional percentage like an added fee

Say I want to pay someone $100.00 but the service I use keeps 3% of the payment I make. Meaning they would only receive $97.00 since they would keep $3. If I increase my payment to $103 they would keep $3.09 meaning they would only receive $99.91.…
Spencer Ruport
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How to calculate 0.5 million into thousands?

I'm no smarter than a 5yr old when it comes to maths (hence I'm here asking for help) so if you could keep that in mind when explaining the answer to me please :-) So as the title suggests, I have a value: 0.5 million and I want to be able to…
Integralist
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$\frac 00=$ ? Why It is un answerable?

Possible Duplicate: Division by $0$ What will be the answer if zero$(0)$ divided by zero$(0)$ Why It is un answerable? $$\frac 00=\space ?$$ Thanks in Advance, Vicky
user1460692
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The arithmetic sequence is 13, 21, 29, 37... Find the least number of terms required for the sum of the sequence terms to exceed 1000.

All I know is that a=13 and common difference=8. I am unaware how to continue from here.
Melonie Seltzer
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Exchange rate question

I'm doing this question for my maths homework and I'm pretty sure I got the answer right but it says I got it wrong. (I got the one highlighted in green correct it's the one below that it says is wrong). Just looking for clarification on if I got…
L Smith
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What does this Theorem mean? Integer as sum of two squares

Theorem 7.2: An integer $n$ can be represented as sum of two squares if and only if, it has factorization in the form: $$n = 2^{\alpha} {p_1}^{\alpha_1} {p_2}^{\alpha_2} {p_3}^{\alpha_3} \ldots {p_r}^{\alpha_r} {q_1}^{\beta_1} {q_2}^{\beta_2}…
Dalton
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Farming plot problem based on squares.

Sunita grows potatoes in his backyard which is in the shape of a square. Each potato takes 1 cm2 in his backyard. This year, she has been able to grow 133 more potatoes than last year. The shape of the backyard remained a square. How many…
Soumee
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Direct and inverse proportionality

Let $x$ is directly proportional to $y$ and inversely proportional to $z$. From above condition we have that: $x=\alpha y$ and $x=\dfrac{\beta}{z}$. Does it follow that $x=k\dfrac{y}{z}$ where $k$ is some constant? If it is true could anyone explain…
RFZ
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Order of operations, BODMAS.

Given the following expression: -7 + 1 - 8 * -10 / 28 - 67 + -54 I resolve it thus: -7 + 1 - -80 / 28 - 67 + -54 -7 + 1 - -2 - 67 + -54 -6 - -2 - 67 + -54 -4 - 67 + -54 -71 + -54 -125 However various online calculators say the answer is:…
tuk
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quicker way of doing this in your head?

I have a question. For $x,y,n \in\Bbb N$, $y$ a power of two, being given $x$ and $y$ is there a faster way to mentally calculate $ny$ where $ny ≤ x< (n+1)y-1$ other than $\lfloor x \div y \rfloor \times y$? Thanks.
octavian
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