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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.

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Confused in basic hex subtraction

I am having trouble thinking in hex terms when making hex subtraction. Example: I am trying to do: 0x503c - 0x40 I am stuck in the part subtracting the 4 from 3. I understand that since in the next position we have 0 we must "borrow" from the 5 i.e.…
Jim
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Geometry Question on Rationalizing Denominators

I am looking to check my answer to the problem : $\frac{5\sqrt{2} + 1}{2\sqrt{2} - 1}$. I think it is $3 + \sqrt{2}$.
IBH
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What is the value of the given expression?

I recently got this question in exam. This seems like a very basic question. But since I made it wrong , It might be my basics are not strong. I solved it this way. 1/1 / 25/1 1*1/1*25 1/25 I got answer as 1/25. But the answer is 25. How ?Can…
vikiiii
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Penguins and maths and penguins

A survey of a group of 103 people about their eating habits found the following: 60 of the people like sardines, 44 like krill, 17 like pizza and krill, 20 like pizza and sardines, 23 like sardines and krill, 7 like pizza, krill, and sardines, 16…
user94655
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Restaurant confusion

I usually meet with my friend Thomas to discuss engineering mathematics on Saturdays. We agreed to be taking turns when buying lunch (I buy this Saturday he buys the next saturday). On two Saturdays when he was supposed to buy he did not have the…
Alexander Mushibwe
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How does commutative property not hold for subtraction?

I don't get why commutative property is not valid under subtraction, because I find that it is for example: $5 - 3 = 2 = -3 + 5$ or rather $5 + (-3) = 2 = -3 + 5$ So how does it not hold true for negative numbers?
Intensed
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Find all values of $k$ such that $x^2+x+1$ is a factor of $x^{2k}+x^k+1$.

Find all values of $k$ such that $x^2+x+1$ is a factor of $x^{2k}+x^k+1$. I tried treating the first polynomial as a root of the other but didn’t get anywhere :(. I also tried substitution to get the second polynomial the resemble the first one but…
Lucien Jaccon
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What is the expansion of $2^{1-s}$?

I'm looking at Eqn. 12 here I tried the power rule $a^m \div a^n = a^{m-n}$ to get $2^1 / 2^s$. But probably this is wrong. Looking at the equation this should probably be $1/2^s$. Can you help? EDIT: I see in this question that the same expression…
zeynel
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Significant Digits for the Sum of Three or More Numbers

When adding three or more numbers together do you add two at a time, while applying significant digits to each sum of two, or do you sum the whole thing, then modify it to express the significant digits. For example, which of the following is…
Nathan
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Chocolate Pieces

With only two linear cuts, it is possible to divide the chocolate cue represented as a matrix of rows 4 and columns 5 so that Aldo gets half, Bruno a fifth, to Ciro the remaining part. How much does Ciro get as a fraction? Answer this…
Sebastiano
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If multiplication is not repeated addition what is it?

I always thought multiplication meant repeated addition. Consider $$4 \times 3 = 12.$$ This the same as $$4 + 4 + 4 = 12.$$ Now consider $$\frac{1}{2} \times \frac{1}{2} = \frac{1}{4}. $$ If I use repeated addition approach, then I get $$\frac{1}{2}…
troy beckett
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Let $k$ divides both $m+2n$ and $3m+4n$, prove $k$ also divides $m$ and $2n$

For any natural numbers $m$, $n$ and $k$, such that $k$ divides both $m + 2n$ and $3m+4n$, $k$ must be a common divisor of $m$ and $2n$. I can confirm this postulation by putting trial and error values, say $m=10$, $n=5$, $m + 2n = 20$ & $3m + 4n =…
Saravana
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Another clock synchronisation problem

I previously posted "a clock synchronisation problem" but now think that I was asking the wrong question. My aim is to look for small errors in time of the local computer compared to a more precise time server over a period of tens of minutes. The…
user36093
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Number game: can this only be solved by brute force?

let be a number with k-cipher $ number= \sum_{n=0}^{k}a_{n}10^{n} $ this number satisfies $$ \sum_{n=0}^{k}a_{n}10^{n} = 2\prod_{n=0}^{k}a_{n} $$ the number is equal to double the product of its ciphers for k=2 is easy the number is 36 however for…
Jose Garcia
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Why can't we apply the distributive property like this?

If I do $3(6 + 9) = (3 \times 6) + (3 \times9)$, I get the correct answer. But when I am doing $3 \times 6(6 + 9 -12) = (3 \times 6) + (3 \times 9) + (3 \times (-12)) + (6 \times 6) + (6 \times 9) + (6 \times(-12))$, I am getting $54$ and $27$ as…
Steve
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