This is clearly some well-meaning attempt to make maths fun so as to appease the congenitally innumerate, but it's damned inconvenient. I have to open a can of beans for no reason other than so Madeleine can see how many will fit on a teaspoon? We don't have any Corn Flakes in the house — she had to use Rice Krispies. Measuring fingers is fair enough (we decided that thumbs should be excluded).
I drew the line at weighing every pair of shoes in the house, though. I don't even know where every pair of shoes in the house is. It was going to take us an hour to find them all, then we'd either have to weigh them individually on our new kitchen scales (that was so not going to happen) or put them in a box and weigh them in the bathroom.
In the end, I just wrote a message in Madeleine's maths book saying that she understood how to calculate averages and I wasn't going to let her do the shoe-weighing thing.
Maybe I should have said that I'd let her do it on condition that her teacher could tell me the average weight of an edition of The Strand Magazine...