On a recent radio “Kids Quiz” a lad, probably in late primary school,  was asked “What is a quarter of 100”?  He had some difficulty and the radio host attempted to help by saying, “50 is half of a hundred, so what would 25 be”?  Still the lad was unable to answer even though he possessed other knowledge. Thinking of the student protest over climate change and the fact that water vapour makes up the vast amount of greenhouse gas and further, that carbon dioxide contributes a very minor 1 or 2 percent of greenhouse gas, one wonders how many of the student protesters fully understand the perceived problem. For those who understand the small proportion of carbon dioxide in greenhouse gas, I wonder whether they would still be concerned when they know every human and animal expels carbon dioxide with every breath which leaves a miniscule amount of carbon dioxide attributable to industrial emissions. I hope most students use their maths to gain a deeper understanding.
  Ken Grundy, Naracoorte, SA