Children might argue that this isn't true but 3 and 5 are consecutive odd numbers. They're also consecutive primes. The value of the 2 in 825 is 2.
Most children will disagree and say the 2 is worth 20 without hesitation.
Well, its place value is two 10s but its face value is 2. It depends which value we are talking about. Multiplying by 10 makes a number 10 times bigger.
Some might fall for this and agree. But what about 0 x 10?
Carefully laid statement traps can raise a few eyebrows, start a bit of head scratching and deepen understanding. Try some yourself and teach children a lesson they'll never forget
John Dabell is a numeracy consultant and teacher trainer