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.

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The commutative law of multiplication.

The commutative law of multiplication states that: If '$a$' and '$b$' are any whole numbers, then '$a · b = b · a$'. I've been looking for why multiplication has this property and how is saying that 3 times 4 the same thing as saying 4 times…
Ashraf Benmebarek
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Why $(255.71 - 255.61 - 0.1)$ is not $0$?

Why $(255.71 - 255.61 - 0.1)$ is not $0$? I used google calculator. It produces the result $-5.689893×10^{-15}$. Although, $(50.71 - 50.61 -0.1)$ produces the result $0$.
Salah Uddin
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Basic mathmatical concepts( multiplication)

Here is a conundrum I pondered upon while solving an equation - 2x2 , generally means we are adding 2 two times , that is , 2+2 Then , (-2)x(-2) , should go like this (-2)+(-2)=-4 , But , that's not true , the answer is +4 . Can anybody figure…
Denthruzel
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Decelerated summation of X

Disclaimer: I'm a 19 year old who didn't pay enough attention in math class, so there is likely a very simple solution to this that I just can't think of. I'm writing an algorithm that will run forever. For unrelated reasons, I want to sum up to 1…
Alex Dovzhanyn
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How to prove $(-3) \times (-4) = 12$?

How to logically understand the multiplication of two integers ? Eg: 3 x 4 = 12 (is understandable) -3 x4 = -12 (is also somewhat understandable) But , 3 x -4 = -12 (is NOT understandable) -3 x -4 = 12 (is also NOT understandable) Now , at this we…
NothingIsIrrational
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Multiple divisions

I was confused a bit with a little arithmetic here. For instance $1÷1÷2$ and $2÷3÷7$. BODMAS isn't effective in this case. My question is this: $2÷3÷7$ Am I to divide $2/3$ by $7$ or divide $2$ by $3/7$??
Orestes Dante
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2 series questions (arithmetic)

So if I borrow money and, to pay it back, I pay 50 for my first month and then 25 more each additional month for 12 months, How much am I paying in total after 12 months? I’m thinking $a_1=50$ and $d=25$ so $a_{12}=(n-1) \cdot 25+50$ right? So…
K Math
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How to quickly solve the following expression

How do I solve the following equation: ABB (base 16) + 101 (base 16)? I know how to do it the long way (converting the bases to base 10 and then adding them). But is there a more efficient way without converting the numbers to base 10?
Stack Hero
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Arithmetic Series

In a race, 8 apples are placed 5 meters apart on straight line, the first being 5 meters away from a basket. A contestant starts from the basket and puts one apple at a time into the basket. Find the total distance a contestant must run to finish…
Jamillah Macapundag
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What does this expression mean?

This is my first time writing, I hope this is the right forum for this. What does this mean? "fraction numerator 48 over denominator square root of 16 to the power of begin display style 3 over 2 end style end exponent end root end fraction minus 3…
Mrsalladhead
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Round based on number of digits

I am not a mathematician, but a programmer. My task is to round integers as follows: 12 → 12 115 → 120 1115 → 1100 11115 → 11000 So you see only the first two digits are precise - the others are just filled with zeroes after rounding the first 3…
ESP32
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Calculating kg per box with loss

He I am not to good in math but I have a situation I need to calculate. Sorry if this looks stupid I really doubt my self if it comes to calculating numbers. I have the following numbers: gross kg: 100kg loss due to production: 2kg per box invoice…
botenvouwer
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adding numbers with infinite decimal expansions

Suppose a,b are real numbers constructed in some well-defined logical way, for example having in their decimal expansion the sequence of all odd & all even numbers respectively: a = 0.135791113151719.... and b = 0.2468101214161820.... I think that…
exp8j
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Deciding if a simple operation involves the associative or commutative laws, and if not, what other axioms can explain it

Can the following two examples be explained by the the commutative and/or associative laws? If not, is there another axiom that does explain them? $(4 \times 5) + (4 \times 5) + (4 \times 5) + (4 \times 5) + (4 \times 5) = 5 \times 20$ $100+4 = (50…
antipoemas
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How to estimate diameter of a roll of paper

Calculate the diameter of a roll if a paper with thickness 0.14mm and 1100m is wrap around the roll, given the roll have a diameter of 92.2mm. For this question i tried two method Consider total surface area wrap on the roll=length*paper…
chuackt
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