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
0
votes
1 answer

Square Root in inequalities

I thought I could be able to find an explanation of this (and perhaps I knew it a long time ago) but I cannot find an answer now. If I assume that $b^2 \leq |x|$, then is it true that both $b \leq \sqrt{|x|}$ and $b \geq - \sqrt{|x|}$ ? I've…
Dan
  • 3
0
votes
4 answers

How does this sum work?

It seems if base number $a$ is a natural number and the exponent $n$ is an odd number greater than or equal to $3$, then: $f(a, n) =\displaystyle\sum_{i=1}^{a^{n-(n+1)/2}}{(2ai-a)}=a^n$ Such as $f(3, 7) = 2187 = 3 ^ 7$ How does this sum work? How…
miket
  • 1,069
0
votes
0 answers

Decomposition of a real number in base $b$

We've had a class today about decomposing a real number in base $b$ and saw the following theorem : Let $b\in\mathbb{N},b\geq2$. For all $x\in\mathbb{R}_+$, there exists a unique sequence $a\in\mathbb{R}^\mathbb{N}$ such as: $\forall…
Hippalectryon
  • 7,730
0
votes
2 answers

Division of Decimal Real Numbers (w/o calc)

I'm getting stuck with what should be something easy for me, have been unable to find a tutorial online. How would I do calculations like: 35.7 / 4.4 or 15.8 / 1.9
Marcus
  • 103
0
votes
2 answers

What does increase globally by percentage mean?

For simplicity sake: Please can you explain to me what does this mean...."trade increases globally by 10%"? assuming Country A = 100 assuming Country B = 100 does it mean.... 1) 10% for each country so new trade means Country A = 110 Country B…
DiscoDude
  • 139
0
votes
2 answers

How to calculate value of x in (1875+y):(x+y)=165

I need to solve this equation but every time I get a different result.Ive tried "find out $x$" calculators online but they fail with "error" or "invalid [...]". The equation is $(1875+y):(x+y)=165$ (I don't know what tags to use for this question)
user154731
  • 11
0
votes
2 answers

Know total amount. Must divide in two parts so that one part is 10% from another part.

I know total amount. Must divide the total amount in two parts. Smaller part (amount) is 10% of bigger part (amount) so that smaller part plus bigger part is total amount. So total is 17091.54 Bigger part is 15537.76 Calculate 10% from 15537.76 and…
Andris
  • 103
0
votes
1 answer

proof of uniqueness (hint) $f(m,n)=n+1$ only if $n \ge m$

I'm a bit confused about this proof. let define on $\Bbb N$ a binary fucntion $f$ that satisfies (1) $f(m,n)=n+1$ if $n \ge m$ and (2) $f$ is commutative if I write the values of $f$ in a 2x2 table using (1) I see that the commutativity makes the…
MphLee
  • 2,472
0
votes
1 answer

What is the smallest division without a fraction?

Is there a mathematical formula to calculate the smallest division of a fraction with both numbers not being a division? I'm not a mathematician (and not English), so I hope I use the correct terms. Example: $\frac{300}{400}=\frac{3}{4}$. But what…
Kees C. Bakker
  • 181
0
votes
1 answer

How to add up multiple intervals and check if they complete a known interval?

If my initial/known interval is [0,20) or length 19 And the 3 intervals are: [0,5), [5,10), [10,20) Using the standard interval addition formula: [a,b]+[c,d] = [a+c,b+d] I get the result [15,35) [1] not [0,20) How do I multiply them to check if they…
izolate
  • 101
0
votes
2 answers

Why Can't We Divide by Zero?

It always seemed to me any number X divided by zero would simply be X, since we're dividing by nothing, so then the original number wouldn't be altered. Why isn't this true? Can this ever be true?
Amy
  • 19
0
votes
1 answer

How can I find the price of house and the garden?

A house and a garden were bought for 1000$, the cost of the house was 5 times that of garden.Find the price given for each. (Actually I don't have any guidance book to solve this type of questions I have got a whole exercise of this type of…
Karim Ghazali
  • 15
0
votes
1 answer

Another fascinating number chain!!

Take any two digit number none of whose digit is $0$. Now add the product of the digits in that number. if number becomes three digit number take last two digits. you will find a chain of numbers or a multiple of 10 after repeating this process:…
Satvik Mashkaria
  • 3,636
  • 3
  • 19
  • 37
0
votes
2 answers

Fastest way to do large additions?

In our book, in the statistics chapter, we have to add a large amount of numbers, especially for finding the mean of some given numbers. Most of the students in our class can do it easily in <30 seconds, but I am a little bit slow with calculations,…
Kartik
  • 1,413
0
votes
1 answer

Geometric Progression related question.

In a sequence, first term a1 = 100 and nth term, an = 100 + (an-1)/5 If for some integer k, a50 lies between k and (k + 1), then k =
Bharthan
  • 141
1 2 3
…
99 100