One hundred and twenty-three teams of students competed in the event in 2018 from 31 schools in Whanganui and the wider Whanganui area.
There are four members to a team, one team member retrieves each question and takes it back to their team to figure out.
The team has to work out the answer as quickly as they can, then take it to be judged and if they get it right, they get the next question, but if they get it wrong, they try again.
If a team decides that they can't answer a question, they can pass and they have 30 minutes to complete them all.
"The kids love it and we love it too," Duncum said.
"We have a little committee made up of teachers from various schools and we choose people to write the papers.
"Then they get moderated, typed, printed and put into folders."
Duncum said one student of note was Year 8 Glen Mallett, who has won Mathex four years in a row, having started in the earliest year group possible, Year 5.
"They all went really good, though, I was delighted with the results."
"It shows the kids that maths is fun, they're doing maths, but they're having fun as well and it's always good for kids to work co-operatively too."
Results:
Year 5: First with 20 (stopped the clock in 22 minutes) = Fordell School (Hamish Cranstone, Maggie Pearce, Chase Rowe, Catie McGregor). Second with 16 = St Johns Hill School 1 (Zuoan Wu, Matt Smith, Caleb Richardson, Youqi Wu). Third with 12 = Mosston School 1 ( Monique Smith, Bailee Fernandez, Sophie Loveridge, Lucas Clapham).
Year 6: First with 16 = Westmere School 1 (Kane Wilson, Levi Toy, Hadley Wilson, Cody Campbell). Second with 15 = St Georges School 2 (Jimmy Lithgow, Rex Liu, Saffron Crook, Harrison Richmond). Third with 13 = Fordell School C (Anya Sewell, Blake Sollitt, Niko Te Kahika, Thomas Dwyer).
Year 7: First with 20 (stopped the clock in 20 minutes 24 seconds) = Huntley School (Jack Trotter, Sam Cranstone, Angus Pearce, Falcon Proffit). Second with 17 = Waitotara School (Toby Corcoran, Elijah Flewin, Cooper Mackintosh). Third equal with 16 = Whanganui Intermediate School 1 (Charlie Moorhead, Jesse Carson, Ivan Adams, Jihoo Kim) and Whanganui Intermediate School 2 (Carter Baum, Siobhan Sarkar, Bede McDouall, Noah Jones).
Year 8: First with 20 (stopped the clock in 17 minutes 57 seconds) = Whanganui Intermediate School 1 (Levi Hoekstra, Philip Dale, Glen Mallett, Ethan Sutherland). Second with 15 = Whanganui Intermediate School 2 (Eliza Maxey, Nikki Forlong, Charlotte Stent, Sophia Bedwell). Third with 13 = Westmere School 1 (Alex Sturzaker, Alyssa Hartley, Sam Greaves, Timothy Christiansen).