Questions on arithmetic operations in Mathematica.

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90
votes
1answer
1k views

Why are numeric division and subtraction not handled better in Mathematica?

There is something that has been troubling me for a while. At least through version 10.0 the performance of a / b and a - b is ...
24
votes
6answers
2k views

Insert $+$, $-$, $\times$, $/$, $($, $)$ into $123456789$ to make it equal to $100$

Looks like a question for pupils, right? In fact if the available math symbol is limited to $+$, $-$, $\times$, $/$ then it's easy to solve: ...
25
votes
1answer
627 views

Is there a difference between Divide[a,b] and a/b?

In this comment it was asserted that Divide[a,b] and a/b are different, though the documentation indicates that they are the ...
2
votes
2answers
317 views

Permanently rounding numbers/values to a given number of significant figures

I am searching for a simple way of rounding and setting an input to a desired number of significant figures. There are a vast number of posts that discuss similar problems, but none address this ...
26
votes
2answers
572 views

Should 0 * 5ft be 0 or 0ft?

After playing with the new quantity system in Mathematica 9 for a while, I keep stumbling over this issue: 0 * Quantity[1, "Meters"] is not the same as ...
7
votes
2answers
678 views

How to do binary calculation´╝č

For example, $a=0.10101$ in binary representation. Then how to calculate $a^2$ directly in mathematica? Is there any function turning binary into decimal? I only found its inverse...
10
votes
3answers
5k views

Expressing a decimal as a fraction in lowest terms

How can I express a decimal such as 0.1845095405274387 as a fraction in its lowest terms?
5
votes
1answer
248 views

Why can't I remove Orderless from Plus?

I am making some random algebra equations, and I want to have the ordering be random too, such that if my random equation generator makes x+1, the output stays ...
4
votes
0answers
90 views

Simple arithmetic with Irrationals fails [closed]

While solving a simple puzzle that asked for a few calculations in plane geometry, I ended up with this expression: $-\frac{55}{2}+\frac{\sqrt{27233}}{2}+\frac{1}{2}(55-\sqrt{27233})$ Or, in ...