It's the moment all parents dread – your child asks for help with their homework and you haven't got a clue what the question means, let alone what the answer is.
Half of British mums and dads admit they would fail their secondary school exams if they had to take them again, a survey has found.
Long division, the elements of the periodic table and even the dates of the two world wars are among the things parents have forgotten from their school days.
Some 44 per cent say they have no idea when it comes to helping with secondary school homework, while a third (34 per cent) can't help their primary school-aged children.
Trigonometry (52 per cent), Pythagoras theorem (46 per cent), algebra (46 per cent), calculating Pi (39 per cent) and the periodic table (35 per cent) all leave parents scratching their heads.
Some 15 per cent have forgotten most of the flags of the world and 21 per cent admit they no longer know the difference between a noun, a verb and an adjective.
One in three have no idea how to convert fractions, while a similar number dread long division cropping up. The difference between types of triangles (26 per cent) and the dates of the two world wars (19 per cent) also leave mums and dads flummoxed.
