5 Smart Investing Strategies The slideshow presentation that you would like to view is too large for your current screen resolution. Click here to view to view the slideshow at full resolution. Launch Presentation » Share | Related Content The Rule of 72 Do you know how long it may take for your investments to double in value? The Rule of 72 is a quick way to figure it out. Estimating the Cost of College This worksheet can help you estimate the costs of a four-year college program. 5 Smart Investing Principles Principles that can help create a portfolio designed to pursue investment goals.