Highley Primary School wanted to celebrate the special occasion by stepping away from the usual day-to-day curriculum and showing the fun side of maths.
And what's more fun that getting the headteacher to lie on the floor while pupils estimate his height using their feet.
Luckily for the students at Highley Primary School, headteacher Mr Plim was a good sport and they were able to have a go at guessing his height.
Lisa Butler, maths leader at the school, said they had a great time celebrating World Maths Day.
"The children are having a break from standard day-to-day maths lessons and doing something a bit different, but still to do with maths," she said.
"We have all sorts of things going on throughout the day. There are 'estimation stations' where children can estimate things like timing a minute or seeing how far an acorn travels when you blow it. Each class is making maths games in lessons, or using other skills to help solve problems, like literacy.
"We have various people from the local community Zoom calling in to show the students how they use maths in their day to day jobs. It is all about enriching the curriculum. All year groups are involved, from reception up to year six. But they're all doing their own thing in classes.
"One of the activities planned is for the children to estimate how many of their feet would make up the height of our headteacher Mr Plim. He had to lie on the floor and the kids estimated how many feet would make up his height. Its about using their maths skills to do something that they think is actually fun."