Rounding Rules

I have a situation where I have rounding rules to apply the the results of 2 fields based on the results value.
>10 rounded to the nearest integer. No problem there.
The other 2 are: <=10 >5 is rounded to the nearest .5 and >5 rounded to the nearest .1
I understand Switch and case, just trying to work out the math for the rounding

Thanks for the assist
David

 

Round to .1 decimal:
var rounded =Math.round(number *10)/10;

Round to integer:
var rounded = Math.round(number);

Round to .5 decimal
- will require an if else statement if > .5 or >= .5

 

Whoops, I meant > .5 or <= .5

 

Thank you much. Been messing around with the math. Working well.
I am trying to get my head around switch. Seems straight forward, but no output to the field 'gd_TTTmm_rnd.value'
The values output by themselves until I added the switch

var tttmm = ((.2*(((.025*pd)+(.3*mod))+19))*sqrrtexp)

switch (tttmm)
{
case (tttmm > 10):
gd_TTTmm_rnd.value = Math.round(tttmm);
break;
case (tttmm < 10 && tttmm > 5):
gd_TTTmm_rnd.value = Math.round((tttmm*10)/10);
break;
}