Approximation and Percentage Skills in DI

What you will be able to do

• Round each figure to a friendly value before dividing, when the options allow it.
• Recall the fraction equivalents of the common percentages.
• Apply percentage-change shortcuts without writing the full formula.
• Compare two ratios by cross-multiplication rather than dividing both.

What is inside this lesson

1. 1Why the arithmetic has to be quick
2. 2Fraction equivalents of common percentages
3. 3Round, then divide
4. 4Percentage-change and ratio shortcuts
5. 5Worked example: weekly footfall at five branches
6. 6When not to approximate
7. 7Quick revision
8. 8Practice