Kelso

Gerald Thurman brings us this sign from the California. This sign is in a very remote area, where its mathematical significance is only shared by precious few.



The math here is wonderful, and rewards patient observer. The answer isn't obvious, and most people would likely miss it, but not Mr. Thurman.

$$(36 \div 18) \times (35 - 15) = 40$$

This sign is in Kelso, California in the Mojave National Preserve. It is located on Kelso Cima Road on the northeast corner of the intersection with Kelbaker Road.