4. To calculate sales tax on an item, multiply
   the price of the item by seven and move the
   decimal point two places to the left. Mentally
   find the amount of sales tax on each item.
   Then add that amount to the price of the item
   to find the total cost.
   a. A bag of flour priced at
   Amount of sales tax:
   Total cost:
   b. A gallon of milk priced at
   Amount of sales tax:
   Total cost:
   A bag of rolled oats priced at
   Total cost:

To find the sales tax on each item, you can apply the quick method: multiply the original price by 0.07 instead of doing all the decimal moving. For the bag of flour priced at $10, the sales tax is $0.70, making the total cost $10.70. For the gallon of milk priced at $4, the sales tax is $0.28, which brings the total to $4.28. Lastly, for the bag of rolled oats priced at $6, the tax comes out to $0.42, leading to a total cost of $6.42.

Now, here’s a fun fact: sales tax originated in the early 20th century to help fund government services! In the US, the first state to adopt a sales tax was Mississippi in 1930. Imagine how different prices would be today without it!

If you’re out shopping and want to avoid sales tax surprises, consider checking your state’s sales tax rate ahead of time or keep a calculator app handy! A common mistake people make is forgetting to include tax when budgeting, so always plan for that extra percentage to avoid stretching your wallet too thin.