Calculation of percentages of numbers without a calculator by decomposition.
Students were shown how to calculate 1% and 10% by manipulating place value
2% is calculasted by doubling 1%
3% is calculated by adding 1% and 2%
4% can be calculated by doubling 2%
5% can be calculated by adding 2% and 3%
Once we have 1% 2% 3% 4% 5% and 10% then any percentage can be
constructed by addition
We practiced as a class on the interactive whiteboard