**Lower Elementary:**

*Question: *Grace received 2 boxes of chocolates. Each box contains 15 pieces of chocolate. If Grace eats 4 pieces, how many does she have left?

*Answer: *26 pieces of chocolate.

*Solution: *To find the total number of pieces Grace started with, double 15. She has 30 pieces of chocolate originally. She ate 4, so subtract 4 from the total. 30 – 4 = 26 pieces of chocolate.

**Upper Elementary:**

*Question: *Megan wants to buy 30 Valentine’s Day cards for her friends. The store sells them in packs of 10 for $6.50. If Megan pays with a $20 bill, how much change will she get back?

*Answer: *50 cents

*Solution: *Megan pays $6.50 for every 10 Valentine’s Day cards. Since she wants 30 cards, she will need 3 packs of cards (10 + 10 + 10 = 30). Paying $6.50 for each will be $6.50 + $6.50 + $6.50, or $6.50 × 3. Thirty cards cost $19.50. The amount of change she will receive is 50 cents ($20 – $19.50 = 50 cents).

**Middle School:**

*Question: *Kyle is going to pay for a Valentine’s Day dinner. The bill is $85 without tax. Kyle wants to give a 20% tip on the bill before the tax is added. The tax is $5. What is the total amount that Kyle will pay?

*Answer: *$107

*Solution: *Algebraic:

Multiply the bill by the tip percent. $85 × 0.2 = $17

Number sense:

20% of a number is the same as 1/5 of a number. 1/5 of 85 is 17, so 20% of $85 is $17

Add the tip and tax to the bill to get the total: $85 + $17 + $5 = $107.

**Algebra and Up:**

*Question: *Jordan is going to spend $20 on a bouquet of roses and tulips. The florist sells roses for $4 each and tulips for $3 each. If Jordan purchases 6 flowers, how many of each are purchased?

*Answer: *2 roses and 4 tulips

*Solution: *One way to solve this is to use a system of equations. Let r be the number of roses purchased and let t be the number of tulips purchased. The two equations are:

(1) The whole is equal to the sum of its parts: (number of roses) + (number of tulips) = (number in bouquet): r + t = 6

(2) Total cost: (cost of roses) × (number of roses) + (cost of tulips) × (number of tulips) = (total cost of the bouquet): 4r + 3t = 20

Let’s solve this system of equations using elimination (you can also solve this using other methods such as graphing or substitution).

r + t = 6

4r + 3t = 20

Multiply the top equation by –3:

–3r + –3t = –18

4r + 3t = 20

Add the two equations together (so that the t can cancel):

r = 2

Plug this into equation (1) and solve for t:

2 + t = 6

t = 4

Jordan buys a bouquet of 2 roses and 4 tulips.