Whenever I talk about the price of gas at the pump, I make the mistake of ignoring the 9/10 tacked onto the number I see on the sign and assume a price that’s one cent lower than the actual price. Most people do that, because the fraction is written in small print and seems insignificant when you’re talking about prices in the range of $4-$6 per gallon. It wasn’t insignificant back in the 70s and before, however, when gas cost less than $1 per gallon. Gas stations aren’t the only places you see fractional pricing; retailers of all kinds do too. Setting the price for an item at $24.99 instead of $25 (for example) tricks consumers into thinking the price is less than it actually is. There’s an element of that in fractional gas prices, but it’s a bit more complicated. So why did gas stations use this pricing then, and why do they do it now? We checked in with fuel management specialist Eliot Vancil and automotive journalist Michael Satterfield to find out.…