Spreadsheet

Lay the quantities out as cells and wire the relationships as formulas, so changing one number pushes the change through every dependent number at once. Best when the question is about amounts moving over time, not about which branch to take.

Lay the quantities out as cells and wire the relationships as formulas, so changing one number pushes the change through every dependent number at once. Best when the question is about amounts moving over time, not about which branch to take.

Example

You build 12 rows, one per month: income, fixed spending, savings balance, and a cell holding the $38,000 renovation. Push the renovation from March to September and the balance column instantly shows you never dip below $9,000.