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.

6283 questions
2
votes
2 answers

What the set $I$ of invertible elements in $\mathbb{Z}_{9}$?

$5.2 = 1$ The set of invertible elements in $\mathbb{Z}_{9}$ is $I = \{1,2,5\}$. Q1: Is it correct? I was also asked to show that it is not isomorphic to $S_{3}$ How can I show that it is not isomorphic? Thank you.
Zouhair El Yaagoubi
  • 1,193
2
votes
1 answer

Adding Fruit Together.

! If the image above doesn't show, the equation could be rendered as follows: $$\frac{a}{b+c}+\frac{b}{a+c}+\frac{c}{a+b}=4$$ How would you go about solving this? Trying to do LCD and substituting does not seem to work well.
Steve Byer
  • 53
2
votes
1 answer

The sum of 2 positive integers is 2310. Show that their product is not divisible by 2310.

I'm not sure how to start. Is 2310 some special number?
Gerard L.
  • 2,536
2
votes
3 answers

What is the mathematical formula for Square Root?

I wasn't at school when we were learning this, and I've forgot how to calculate a square root on paper using a formula? Can anyone please help me? What is the formula? I need this to write an algorithm for my college assignment home work. Thanks!
user32596
2
votes
2 answers

Generalising arithmatic operations

Is it possible to have a continuous function $f$ s.t. $$f(x,y,1)= x+y \\f(x,y,2)=xy\\f(x,y,3)=x^y\ \\ f(x,y,-1)=x-y \\ f(x,y,-2)=\frac{x}{y}\\ f(x,y,-3)=\sqrt[y]x$$ etc? so we can have things like $f(x,y,1.5), f(x,y,5)$ defined? Are there such…
jimjim
  • 9,675
2
votes
4 answers

Rule for multiplying rational numbers (follow-up)

I was thinking about the rule where $\space\frac{a}{b}\cdot \frac{c}{d}=\frac{ac}{bd}$ and why it worked, and I found this question: Rule for multiplying rational numbers. The best answer was: Did: One knows that $a/b$ may be defined as the number…
Max
  • 1,275
2
votes
1 answer

Are there any other solutions to $x^y = y^x$, $x \neq y$, $x, y \in \mathbb C$?

As you know, $x = 2$, $y = 4$ is the only solution in integers. Well, also $x = 4$, $y = 2$ if you want to be a smart aleck about it. But what if you expand the search to include $x$ and $y$ that are rational, or irrational, or imaginary, or…
Robert Soupe
  • 14,663
2
votes
1 answer

How many significant digits should be retained on powers?

An example: $$5.1^4=676.5201$$ But the base of the power only has two significant figures. In this case, How this result should be reported?
Another.Chemist
  • 175
2
votes
3 answers

evaluation of mathematical expressions - always left to right?

Is there a rule in mathematics that states that expressions shall be evaluated from left to right assuming that all operators in the expression share the same precedence? e.g. given the expression 6 / 2 * (1 + 2) is there a rule so that only (6 /…
yas4891
  • 123
2
votes
0 answers

Why is $a^0=1$ and not $0$?

Since I learned exponentiation in School, me and my classmates had this one question stuck in our brains. Why is $a^0=1$ and not $0$. Wouldn't it make more sense if it equaled to $0$, since $a$ is multiplied by itself $0$ times, it should equal $0$.…
user408996
2
votes
2 answers

How to calculate orginal amount?

It might be simple question for people over here... I just get the bank statment where I get 41000 bucks, But they mentioned that they cut 2% from orignal amount... (means i get the 41000 after cutting 2%) Now, I am not able to calculate orginal…
user1668543
  • 23
2
votes
1 answer

Division and multiplication – reordering operands and operations

Precedence with division and multiplication matters. For example: $$ (80 \div 10) \times 5 = 40\\ 80 \div (10 \times 5) = \frac{8}{5} $$ More generally, I might write: $$ (A \div B) \times C \neq A \div (B \times C) $$ (Although sometimes that…
jds
  • 2,274
  • 3
  • 24
  • 35
2
votes
1 answer

A frog hops and lands exactly 1 meter away at a time..

I am stuck with the following problem: A frog hops and lands exactly 1 meter away at a time . What is the least number of hops required to reach a point 10 cm away ? The options are: 1.$\,\,1$ 2.$\,\,2$ 3.$\,\,3$ 4.It can't travel such a…
learner
  • 6,726
2
votes
4 answers

Why is modulus not a basic arithmetic operation?

In school I learned that there are four basic arithmetic operations: addition, subtraction, multiplication, and division. I always wondered why modulus is not a basic arithmetic operation. Is there any explanation that is also understandable by a…
RoflcoptrException
  • 173
2
votes
2 answers

Finding function to return number sign

My question is two-folded. Both parts pertain to the fact that I want to find an arithmetic function $f(x) $ that returns $-1$ or $1$ when $x < 0$ or $x > 0$. I don't really care about $f(0) $. But I want this function to calculate the sign of $x $…
RGS
  • 9,719
1 2 3
…
99 100