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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.

6283 questions
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Why does square rooting a negative number never give us an answer?

I used to do this on my calculators and it never worked! I think it's because you can't multiply any number by itself to get a negative number. Is that even true? I think it is! I've tried it out and it never worked! Look…
VladInTheTaylor
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Measuring equal distances between points on a line

I have a 36 inch piece of wood (Length) I will placing 6 coat hanger hooks along the length of the wood. The first hook will be placed 1 inch down the length from one end and the last hook will be placed 1 inch from the other end of this 36 inch…
Joe
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How to show that bound?

How to show that $\prod\limits_{i=1}^k \dfrac{k+i}{4i}$ is less than or equal to $1/2$ for all $k \ge 1$ Integer. I coulden't understand the answer in How to prove the bound on the probability?
Pqqwetiqe
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Multiplying a infinite number with a rational number?

Please do not down vote this question. It may be stupid, but I wonder. Why is it that we cannot multiply $3.99999\cdots$ by $4$ and write $16,....$?
Marion Crane
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What am I doing wrrong here that violates the rule that "order doesn't matter when multiplying and dividing?"

5 / 1 * 4 if I do the 5/1 first: (5 / 1) * 4 = 5 * 4 = 20 (final answer is 20) if I do the 1 * 4 first: 5/ (1 * 4) = 5/4 (final answer is 5/4) What am I doing wrong?
user156964
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I have problem solving this system

I have given arithmetic progression and I know that: the sum of the first element(A1) and the fifth element(A5) is equal to 18 A1+ A5 = 18 and that the sum of the first and the third element minus the seventh element is equal to 1 A1 + A3 - A7 =…
user193785
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Unique Number Calculations

What do you call numbers you can add together that will always be unique. $a = 1,$ $b = 2,$ $c = 4$ Any combination of the above will always result in a unique number. eg: $7 = abc,$ $6 = bc,$ $3 = ab.$ Sorry if this is a simple maths question, I…
Nicholas Mordecai
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Irrationality proof

Prove that $\sqrt{7-\sqrt{2}} $ is irrational My idea is the following $\sqrt{7-\sqrt{2}} \in\mathbb{Q}$ $w^2=7+\sqrt{2}$ $w^2-7=\sqrt{2}$ thus w cannot be rational is this correct? edit: or maybe i can assume $\sqrt{7-\sqrt{2}} =\frac{m}{n}$ and…
kamakrowski34
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Chopping arithmetic

I would like to use chopping arithmetic for 3 digit chopping for the following: $a)\pi$ and $b) 456788.1234567$ My guess is that it is $3.141$ and $456788.123$, but my book says the pi after chopping is $3.14$. I'm wondering if that's right since if…
arno
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How to divide by 3.5 by multiplying

I want to divide a variable by 3.5, only through multiplying it with a value under 1. How do I find out what I should multiply by?
SomeoneOrNoOne
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linear equation for vertical line

If we want to graph a horizontal line, we will do the following: y = 0x + 3 No matter the domain for x, the range for y will always be 3. Therefore, we have a horizontal line. y = 0(0) + 3 = (0,3) y = 0(1) + 3 = (1,3) y = 0(2) + 3 = (2,3) Now the…
JohnMerlino
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Modular arithmetic Proofs

For all $a$, $m \in\mathbb{Z}$, prove that For all $x \in [a]$, where $[a]$ is the congruence class of $a \pmod m$, $\quad\gcd(x,m)=\gcd(a,m)$. I have no idea where to start for this.
Ian Murphy
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Numerical problems

Arrange the following in ascending order 3 to the power 34, 2 to the power 51, 7 to the power 17. How? Also, please explain.
Vikash
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Divisibility rules of 2, 3, 5, 9 and 11

How can I prove this divisibility rules? $b \in \mathbb{Z}^+$ $2\mid b \Longleftrightarrow 2\mid r_0$ $3\mid b \Longleftrightarrow 3\mid(r_0+r_1+\cdots+r_n)$ $5\mid b \Longleftrightarrow 5\mid r_0$ $9\mid b \Longleftrightarrow…
Raphael Tomé Santana
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What is the sum of one + one in a 26 letter number system

A number system based on 26 uses the letters of the alphabet as its digits, with $A = 0, B = 1, C = 2, D = 3, E = 4, . . . , Y = 24,$ and $Z = 25. $ What is the the sum: ONE + ONE = in this system
marth-anna love wuanti
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