A TKer subscriber recently pointed out that if your investment is down 20%, then you'd need a 25% gain from the current level to return to the initial level.For example, if your investment of $100 falls 20$20), then you will have an asset worth $80. To return to breakeven, the value of your$80 asset would need to increase by 25% (or $20).This is a helpful way of thinking about investing as you look at the red and green arrows in your portfolio. It keeps your math sharp while reminding you that earnin ...