numbas
Display 2 decimals when simplifying
I'm making a question about money, and I'd like simplified numbers to be displayed with exactly 2 decimals, as most prices are.
Something like: $\simplify[decimals=2]{{p1}+{p2}}$ outputting $2.20$ if p1=1.05 and p2=1.15 would be nice.
That's a good suggestion, thanks.
For now, you could use the dpformat or currency functions? You won't get simplification rules applied, so you'll need to beware of things like adding negative numbers.
Thanks, that seems to work fine in most cases, except when the amount is less than 1. Something like {currency(a,'','')} or $\var{latex(currency(a,'',''))}$ for a=0.80 outputs 80 or $80$ instead.
The currency function prefers to render numbers less than 1 using the 'cents' symbol, which is the third argument. For example, currency(0.8,'£','p') would produce 80p. I think dpformat does what you want.
I do want to implement the [decimals=2] option you suggested, so I'm leaving this open.
I missed your mention of dpformat... I made a custom function based on currency: (the number n is the only input)
var s = Numbas.math.niceNumber(100*n,{precisionType:'dp',precision:0});
if(n >=0.995){
if(n%1 < 0.005) {
return Numbas.math.niceNumber(Math.floor(n));
} else if(n%1 >= 0.995) {
return Numbas.math.niceNumber(Math.ceil(n));
}
s = s.replace(/(..)$/,'.$1'); // put a dot before the last two digits, representing the cents
return s
} else {
s = s.replace(/(..)$/,'0.$1'); // put 0. before the last two digits, representing the cents
return s
}