It seems that two years of shameless use of ratio tables have finally paid off; I saw three of my Year 11s independently tackle a non calculator percentages question like this today:
I’m not sure exactly how I would have taught this before I discovered ratio tables; I suppose just pray that they noticed a common factor of 8 in the numerator and denominator to get them to 4/10, then realise that they need to multiply numerator and denominator by 10 to get 40/100.
I’ve previously blogged about how useful I’ve found ratio tables for percentages of amounts, increases and decreases. but I’ll also be adding this permanently to my repertoire for fraction and percentage equivalence from now on. It’s incredibly helpful for those pupils who just refuse to look for factors other than 2!
If you fancy giving it a go, you may be interested in this worksheet:
