One in five adults (or 20%) has forgotten how to work out either fractions or percentages, and even fewer remember how to calculate the mean, the median or the mode, according to a study.

It reveals a perturbing lack of recall among many adults who have forgotten not just the rules of mathematics, but many of the key principles of English and science they were taught at school.

In maths, 35% of the 2,000 adults who took part in the YouGov survey said they would no longer know how to calculate the mode, 31% the median, 28% the mean and 27% the area of a circle.

Respondents were challenged by long division and multiplication, with a quarter unable to remember how to do the former and 23% the latter. Meanwhile, 26% had forgotten how to work out the square root.

In English, many showed a similarly shaky grasp of punctuation with almost one in four admitting to not knowing when to use a semi-colon (23%); 18% the rules governing the use of an apostrophe; and 17% when to use a comma.

More than a third (34%) do not know what an oxymoron is; almost a quarter (24%) have forgotten the joy of similes and a fifth cannot explain metaphors.

The basics of science have faded with 24% unable to remember all the names of the planets in the solar system; 19% said they were unable to either remember or explain the greenhouse effect; while 21% have forgotten photosynthesis.

The least well-remembered topics from the science classroom, however, were mitosis, which 41% adults were unable to recall or explain; the groups in the periodic table, which have been forgotten by 39%; and the detail of the water cycle, forgotten by 24%.

Dr Nick Smith, founder of the Oxford Open Learning Trust, which specialises in distance learning and commissioned the research, said: “Being unable to remember the mean, median and mode, or the correct use of a colon may not seem like a big deal, but the lessons we learn at school remain very much important in later life.



“Whether it’s working out the bill at a restaurant, writing your covering letter or helping kids with homework, basic maths, English and science skills are invaluable.

“Most employers will discount any applicant who seems weak in key skills like writing and arithmetic, whatever the job. Every study has shown that there is a direct link between our proficiency in basic skills, career advancement and prosperity.”