How to calculate half, third, fourth?

Question

I'm trying to calculate some image sizes for Imager.

This works:

{% set imageSizes = [{ height: imageHeight * 4}, { height: imageHeight * 3}, { height: imageHeight * 2}, { height: imageHeight}] %}

But how do i get halfs?

imageHeight * 2.5, imageHeight * 0.5 or imageHeight / 2 does not work.

Edit:
It was my own fault.
I checked the array and only saw width's. I set the images sizes in the CP and to:

{% if imageHeight is not empty %}
  {% set imageSizes = [{ height: imageHeight * 4}... %}
{% else %}
  {% set imageSizes = [{ width: imageWidth * 4}... %}
{% endif %}

I only wrote the half calculation in "if imageHeight" for testing. But the entry i use for testing has only width's...

Answer 1

I'm going to guess something else is wrong in your templates, because all the examples you provided definitely work in Twig. Perhaps you have an error or typo on an earlier line that's preventing your imageHeight calculations from working. I'd also check what imageHeight is set to as that isn't apparent from the snippet you provided; you can check by dumping the value - {{ dump(imageHeight) }}.

• Here's a TwigFiddle showing how the math does work: https://twigfiddle.com/522svb
• Here are the docs on mathematical operators in Twig: https://twig.symfony.com/doc/2.x/templates.html#math