A maths trick that can guess your age and shoe size has sent Twitter into overdrive. The trick has been around for years but recently went viral after it was posted onto the social media site.

You may find this conversion chart helpful when figuring out kids’ sizing for shoes. While this is hardly perfect, it’s a start. Keep in mind this chart is for youth or so-called big kids sizes.

With measurements and a conversion chart in hand, match your numbers to the appropriate size. Most shoe size charts feature both inches and centimeters, but doing conversions in centimeters is a ...