Mental Math Shortcuts

Here’s a collection of time-saving math shortcuts, great for back-of-the-envelope estimates.

Time and Distance

60 mph = 1 mile per minute

• Going 60 mph and the exit is in 10 miles? That’s 10 minutes.
• Been driving a half hour? That’s about 30 miles at highway speeds.

Feet Per Second = MPH * 1.5
MPH = Feet Per Second * 2/3 (derivation)

• 60 mph …
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• Mental math shortcuts, adding 1-100
• Understanding exponents and the natural log
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