Tommy Walsh: Backing the literacy and numeracy drive
A study for the Department of Education's "Get On" campaign found nearly one in three adults (29%) in England could not calculate the floor area of a room in feet or metres - with or without calculators or paper and pens.
Gardeners are no better off.
The research also found that over 10 per cent of adults questioned could not understand the instructions on a packet of seeds.
"But, as we all know, it can be really infuriating when things go wrong - if you find that you've not got enough cement to complete your patio, or you've bought too much wallpaper for your front room.
"This problem is all too familiar and can lead to wasted time and money. I'd encourage anyone who struggles with instructions or numbers this weekend, to call 08000 150 650 to find out more about enrolling on a free course to improve their skills."
The government is using TV personalities like Tommy Walsh in the 'Get On' campaign to try to encourage people with numeracy and literacy problems to sign up for training.
The campaign is part of the government's "Skills for Life" strategy, which aims to raise skills levels in 750,000 adults by 2004.
The education minister with responsibility for adult skills, John Healey, said the research showed that millions of people struggle with literacy and numeracy problems, rather than improving their lives.
"Being unable to calculate an area, or correctly read instructions means that you could be wasting money on unnecessary materials or making mistakes, which will undo all of your hard work," he said.
"But it's not just DIY and gardening that problems with literacy and numeracy can affect - people with good skills in these areas could earn much more money over their working life than someone with poorer skills.
"There are thousands of free courses available across the country to help improve literacy and numeracy."