# Tagged Questions

104 views

### Confused about the $\pm$ sign?

I have multiple questions about the $\pm$ sign, since it seems to confuse me in general... Question 1: Say I have $15=\pm(a+x)$, Can I use the distributive property so it becomes $15=\pm a \pm x$? ...
41 views

### Is there a more rigorous method of notating arithmetic?

Is there a method of notating arithmetic that presents the transformations more explicitly than the standard method? For example. Someone using the standard method might present their solution ...
98 views

### is the decimal notation the “right” notation for arithmetic?

I am considering here the pre-decimal notations such as Roman numerals, Egyptian numerals etc. It seems reasonable that these must all be equivalent. And it seems that decimal notation (i.e. ...
256 views

### What does P(A U B) mean, in terms of real values?

I can't find a proper summary or reference of how to translate formulas in probability notation to arithmetic notation (i.e. when using real values). For example, if $P(A) = .7$ and $P(B)=.35$, what ...
91 views

### How does ZFC describe addition?

Surprisingly, the Wikipedia article on addition doesn't contain the answer. I looked elsewhere online for it, but didn't find it. Intuitively, the cardinal of the union of two sets seemed ...
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### Is there any way to write this number with these limits?

Is there any way to write this number: $$\frac{17+15\sqrt{5}}{7+15\sqrt{5}}$$ Just using the digits $1$, $4$, $7$, $8$, $9$ once each with the following criteria: A maximum of two square root ...
212 views

### Why are the order-of-operations conventions good?

Children are sometimes taught silly mnemonics like "PEMDAS" to remember conventions on order of operations. (I never heard of "PEMDAS" until long after graduating from college, as far as I can ...
212 views

### Order of operations in rotation matrix notation.

I'm trying to convert this equation to C# but I'm not a mathematician and I find math notation ambiguous: See the first matrix in this article: http://mathworld.wolfram.com/RotationMatrix.html ...
105 views

### Dumb percentage question?

Why do we multiply by 100 while calculating percentage ? example : 2/100 * 100 =2%
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### order of operations division

Very dumb question: What is the order of operations in the following: PEMDAS a/b+c = a : b + c (where ":" is the division symbol) 7/1+6 or 7:1+6 in the example below is it 1 or 13?
311 views

### Powers in ASCII text

I have a problem reading a discussion forum post. Namely, in the ASCII text, is 2^3^4 the same as $(2^3)^4$ or $2^{3^4}$?
108 views

### Correct precedence of division operators

Say i have the followingv operation - $6/3/6$, i get different answers depending on which division i perform first. $6/3/6 = 2/6 = .33333...$ $6/3/6 = 6/.5 = 12$ So which answer is correct?
561 views

### What is the “status” of the rule that multiplication precedes addition.

What is the source, or "status", of the rule that multiplication is performed before addition? Is it a definitive property of $\mathbb R$, a property that can be derived directly from the definition ...
129 views

### Radix point notation and significant digits

So, we represent numbers usually in a form of a sequence of digits where each one of them multiplies the power of a base: $13.2 = 1 * 10^1 + 3 * 10^0 + 2 * 10^{-1}$ So that much is clear, perfectly. ...
490 views

### bitwise operations

so my question is what is the order of operations for bitwise operators << & | and also to see if my logic is right with the problem below (x03 << x08)+ x00 = 300 ...
1k views

### What is mathematical basis for the percent symbol (%)?

Percent means 1 part of 100 or 1/100 and is indicated with %. Per mille means 1 part of 1000 or 1/1000 and is indicated with ‰, so it seems that these symbols indicate the mathematical operations ...
7k views

### What is “multiplication by juxtaposition”?

I was reading http://www.purplemath.com/modules/orderops2.htm it shows = 16 ÷ 2[2] + 1 (**) ... = 5 The general consensus among math people is that ...
There is a huge debate on the internet on $48÷2(9+3)$. I figured if i wanted to know the answer this is the best place to ask. I believe it is 2 as i believe it is part of the bracket operation in ...