# The Power Of Ten -Mental Model 060

# Order of Magnitude

An estimate of a variable whose precise value is unknown and estimated to the nearest power of ten.

**Example:** “The biggest epiphany I’ve had this year is that what really matters is the machine that builds the machine, the factory,” he said. “And that is at least two orders of magnitude harder than the vehicle itself.” — Elon Musk

Musk uses the term ‘order of magnitude’ to emphasise the difficulty of building the Tesla factory because exactly how difficult it will be cannot be calculated.

**Wisdom:** “Mathematics would certainly have not come into existence if one had known from the beginning that there was in nature no exactly straight line, no actual circle, no absolute magnitude.” — Friedrich Nietzsche