Click here for the Problem Extension Worksheet version of the Problems of the Week.
Click here for an MS Word version of the Problems of the Week.
Click here for the Canadian Problem Extension Worksheet version of the Problems of the Week.
Click here for a Canadian MS Word version of the Problems of the Week.

Lower Elementary:
Question: Ellie breaks open her piggy bank and finds a half dollar, two quarters, two dimes, a nickel, and two pennies. How much money does Ellie have?
Answer: $1.27
Solution: Ellie has 1 half dollar worth 50¢, 2 quarters worth 25¢ each, 2 dimes worth 10¢ each, 1 nickel worth 5¢, and 2 pennies worth 1¢ each. So, Ellie has 50¢ + 25¢ + 25¢ + 10¢ + 10¢ + 5¢ + 1¢ + 1¢ = 127¢. Since there are 100¢ in a dollar, that means Ellie has $1 and 27¢, or $1.27.

Upper Elementary:
Question: Packs of trading cards cost $3.50. What is the greatest number of packs of trading cards that Kaylee can buy with a $20.00 bill?
Answer: 5 packs of cards
Solution: First, let’s estimate how many packs of cards Kaylee can buy by rounding; $3.50 rounds up to $4.00, and $4.00 goes into $20.00 five times. Let’s try it with the actual value of a pack of cards; $3.50 × 5 = $17.50. That means that if Kaylee buys 5 packs, she’ll have $2.50 left, which isn’t enough to buy another pack of cards. So, Kaylee can buy 5 packs of cards at most.

Middle School:
Question: Logan buys a box of 64 colored pencils for $24.00 and a box of 36 crayons for $12.60. Which costs more, a single colored pencil or a single crayon?
Answer: a single colored pencil
Solution: To find the price of each pencil, we divide the total cost of all the pencils by the number of pencils. Each pencil is worth $24.00 ÷ 64 = 37½¢. Let’s compare to the price of a crayon, which is $12.60 ÷ 36 = 35¢. Since 37½¢ > 35¢, the value of a colored pencil is greater than the value of a crayon.

Algebra and Up:
Question: The value of a painting increases by 2% each year. If the painting is worth $1,000.00 today, how much was it worth exactly 50 years ago?
Answer: $371.53
Solution: We can model the increasing value of the painting with the expression x × 1.0250, wherein x is the starting value of the painting, 1.02 represents the percent increase, and 50 is the elapsed time. We know that after the 50 years, the painting is worth $1,000, so $1,000 = x × 1.0250. To solve for x, we divide $1,000 ÷ 1.0250 = $371.53 (remember to round to the next cent).