It is not often that we perform detailed numerical calculations with only pen and paper.
This unit aims to develop skills that are relevant in a cell-phone-generally-within-reach society:
- Recall of basic number facts;
- The ability to ball park calculations by rounding to one or two significant figures;
- The ability to double or halve, repeatedly;
- The ability to multiply or divide by 5, 20 or 25;
- The ability to convert miles to km, and km to miles. Highway entertainment?
- The ability to compute a tax or a tip.
Getting a calculation correct to three significant figures without technology is a party trick or mental entertainment for those that love arithmetic. Knowing that an answer is within a reasonable ball park is required for any person who uses technology to do their arithmetic.