Most of us have little trouble working out how many milliliters are in 2.4 liters of water (it's 2,400). But the same can't be said when we're asked how many minutes are in 2.4 hours (it's 144).

Shelby Putnam Tupper is founder and creative director of Shelby Designs Inc., a small-but-mighty, full-service, customer-obsessed design consultancy.