Sharing 3/4 of its border with Maryland, DC has a symbiotic relationship with that state. When an urbanist blogger/journalist complains that East of the River (pop. 150,000) is devoid of supermarkets, commenters ridicule him/her: There's at least two each of Food Lion and Giant within 3 blocks of the 'invisible' border. Then there's the tax game: Initiator: "Let's raise taxes. I'll look good when everyone validates me when they raise theirs" Follower: "Our tax rate is at par with this other state. Because of this there will be..." That's what DC is doing to combat revenue loss (and leak: A political game of follow the leader; increasing the sales tax from 5 and 3/4 of a penny to 6 pennies.
So Mary Lou buys a $.75 candy bar in a Maryland store. This is back in 1998, the tax rate is 5%. What did Mary really pay?
Take 10% (move the number to the right by 1 decimal place) and cut by two, add to final. If decimal, round up, that's the way they like it.
Mary Lou's sister, Mary La, buys the same candy bar at $1.09 in the same Maryland store. This is in 2008, tax rate is now 6%. What did Mary really pay?
Do as above, and throw on a 1% (move number to right twice)
5%= 11 cents
1%= 1 cent
12 cents + 1.09 = 1.21
Mary La's brother, Doc, figures it's better to buy his candy in DC, where the tax rate is 5.75%. He goes to Balducci's (to eliminate need to adjust for so-called 'poverty tax') and buys a $4.29 imported Belgian chocolate.
This is a toughy. Take 5%, 22 cents, add the 1%, split that by four and take three parts of it (.04/4= .01 -> .03) The total price is $4.54.
The tax rate goes up to 6%. Now what does he pay? $4.55, and less brainwork.
Virginia, Doc's cousin, buys a 'dixie stick' at the State Fair Shop. The tax rate is 4%, the candy is $.25
Take 1% and multiply by four
Or use 'old math' to get 1 cent as tax for a whopping total of $.26
Della, the other cousin, buys a hoity-toity designer chocolate box at Christiana Mall in Delaware, whose tax rate is 0%. The candy is $19.99. She give the clerk $20.00. How much does she owe the clerk?
In this case, the clerk owes Della a penny.
People from the slide-rule age say that keeping zeroes straight in their head is easier for them than calculator folk