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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Given values of X , find fractions

Solve the equation expressing $x$ in terms of $y$ $$x^2 - 6xy + 5y^2 = 0$$ Given that area of part $A$ of a circle is $$3x^2 - 2xy - y^2 \text{ cm}^2$$ Area of circle is $4x^2$ cm^2 Calculate fraction $$\frac{\text{Area of part $A$ of the…
user307640
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Numbers question

A particular plant in the garden needs to be watered every 3 days , trimmed every 4 days and fertilised every 8 days . If a gardener performs these 3 tasks on Day 1, list the days that the gardener will carry out at least 2 tasks over a 30-day…
user307640
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Computing $10101011 \cdot 1025$

I'm trying to compute the following expression: $10101011 \cdot 1025$ in a simple, easy way without using a calculator, or an elementary school way. I realized that $1025=2^{10}+1$ so I need to compute now $10101011 \cdot 2^{10}+10101011$, How…
Joni
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Can two collections of different size have same A.M., G.M. and H.M?

After following Can two sets have same AM, GM, HM? and the sublime answer of Micah, I am tempted ask the solution of the same question when size of these two sets are not same.
lab bhattacharjee
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what is the meaning of 100% of 100%?

When we say a% of b, we mean 'a' parts out of the 100 parts of 'b'. e.g. 1% of 200 means divide 200 in 100 equal parts and select 1 out of it, i.e. 2 So, what does it mean when we say any percentage of any percentage? like, what is the significance…
Eight
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Decrementing one number, incrementing another, while keeping the same relation to one another

This is a game development question related to math. Apologies if I shouldn't be asking this here, but I'm not good at math and need help with increasing the speed of my game. I have one number responsible for the speed at which the screen appears…
JeffD
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Find a fraction of a part that is shaded

In the figure , O is the centre of the two circles . The circles are divided into sectors of equal sizes. Given that the area of the shaded portion A is twice of the area of the shaded portion B What is the fraction of the figure that is shaded ?…
user307640
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How can we prove that a number is a prime with some limits?

A simple python program implemented a simple fact that the number is prime if no numbers within it's square root including the square root and excluding 1 divide it. Empirically analyzing it for some 50 numbers I found it true and the remaining…
bzal
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Irreducible fraction

Prove that $$ \frac{2}{99},\frac{3}{98},...,\frac{97}{4},\frac{98}{3},\frac{99}{2}% $$ are irreducible. My attempt is: if $a/b$ is irreducible, than $\left( a,b\right) =1$. Now, I choose $a=k,k=2,3,...,99$ and $b=101-k$, hence we need to show…
user217519
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How casting out $11$s works?

Following line are quoted from the book Secrets of Mental Math by Arthur Benjamin and Michael Shermer. To double-check your answer another way, you can use the method known as casting out elevens. It’s similar to casting out nines, except you…
Tharindu Sathischandra
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Rounding currency values

If I have a receipt with the following: 4.37 4.37 Each item discounted at 10% 4.37 * 10% = .44. rounded from .437 4.37 * 10% = .44 rounded from .437 total discount .88 subtotal is 7.87 rounded from 3.933 + 3.933 = 7.866 7.87 * 5.5% tax = .43…
KiloJKilo
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Definition of Division with Remainder

I have a trivial question. When we divide say 5 by 2, quotient is 2 and remainder is 1. However say we divide -5 by 2, then should we have a quotient -2 and remainder -1 or quotient -3 and remainder 1? Some people claim that remainder should always…
Cowboy Trader
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Find no of nuts and raisins.

Grandmother made 20 gingerbread biscuits for her grandchildren. She decorated them with raisins and nuts. First she decorated 15 cakes with raisins and then 15 cakes with nuts. At least how many cakes were decorated both with raisins and nuts?
john_121
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Is there a physical analog for division by a fraction?

Dividing by a fraction seems anomalous in the set of arithmetic operations inasmuch at it appears to have no analog in the physical world. Is this the case? Or is there some physical analog to the arithmetic operation of division by a…
Mowzer
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Profit and loss qn

The cake shop made a profit of $100/3 \, \%$on every cake sold . Calculate the selling price of a $1.5$kg strawberry cake if the profit made was $\$5.40$ My workings and thoughts - I find cost price by -- $100/3 \, \% = \$ 5.40$ $ 100\% = \$…
user307640
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