So why can't young shop staff work out the right change?
Would-be airport firefighters are being rejected for the job because they lack the writing skills needed to fill in logbooks describing how fires have been tackled.
And a major food retailer has had to overhaul its tills so that its employees no longer need to key in the price and quantity of goods on sale but simply push buttons for "croissant," "black coffee" or "fries".
A report this week from the CBI, commissioned by the Government, has provided evidence to back up the seemingly ritual cries from employers that school-leavers' writing and numeracy skills are poor, despite the year-on-year increase in GCSE passes.
Its survey of 140 companies revealed that more than one in three had had to introduce remedial training in literacy, numeracy or both in the last year.
The pressure group said employers were routinely finding school-leavers unable to do maths without a calculator, to handwrite notes legibly or to compose emails without resorting to text-speak.
Richard Lambert, CBI director general, said this was a "sad indictment of how the education system has let young people down".
The examples provided add ample grist to the mill. One food retailer said his young staff were totally thrown if offered pound;10.17 for an item costing pound;5.17.
However things may not be quite as bad as they seem. The companies responding to this type of survey could include a disproportionate number which had a strong interest in raising literacy and numeracy skills, the report admits.
The implication is that a larger study might have found a lower percentage of firms organising remedial work.
And while the survey revealed that a fifth of employers often found that non-graduate recruits of all ages had literacy or numeracy problems, 28 per cent of firms said they had no complaints.
A quarter said new non-graduates did not struggle with literacy, compared to 22 per cent who said that most or all recruits foundered.
Bethan Marshall, a reader in English education at King's college, London, said the CBI's claim was not new. A string of reports, dating as far back as the early 20th century, have bemoaned young people's literacy deficiencies.
The CBI is also on shaky ground when it complains that only 45 per cent of pupils achieved five or more GCSEs including English and maths at C or better last year.
As Dr Marshall pointed out, pass rates have been transformed over the past 20 years. In 1975, just 23 per cent of pupils achieved the equivalent of five or more GCSE grade Cs. In the 1980s, the average level of performance was a CSE grade 4, the equivalent of an F grade at GCSE. Now, 56 per cent achieve at least five grade Cs. National test results have also risen remarkably.
Despite this, the Government will find it hard to dismiss the employers'
complaints, because their experience appears to contrast so vividly with the rising results trend.
"Many employers have lost confidence that GCSEs are a reliable measure of equivalent standards over time," said Mr Lambert.
Only 3 per cent of surveyed firms said school leavers' numeracy skills had improved over the past five years. Thirty-four per cent had noticed a deterioration. The figures were even worse for literacy, with three per cent citing improvement and 45 per cent alleging things had got worse.
Gareth Calway, a poet and head of English at Smithdon high, Norfolk, backs the CBI report. He said he had seen no improvement in pupils' reading and writing since the literacy strategy was introduced.
Mr Calway, who has been teaching since the 1980s, said: "They can say, 'That's a metaphor' and they can do an exercise that has been set up to test that knowledge. But they cannot use them."