**Lower Elementary:**

*Question: *Joey has 7 coins. 3 are nickels and the rest are dimes. How much money does Joey have?

*Answer: *55¢

*Solution: *If Joey has 3 nickels and has a total of 7 coins, then that means he has 4 dimes (7 – 3 = 4). One nickel is worth 5¢, two nickels are worth 10¢, and three nickels are worth 15¢. One dime is worth 10¢, two dimes are worth 20¢, three dimes are worth 30¢, and four dimes are worth 40¢. Since three nickels are worth 15¢ and four dimes are worth 40¢, that means he has a total of 55¢.

**Upper Elementary:**

*Question: *If you needed to buy 24 batteries, what would be the better buy and by how much: buying 6-packs of batteries for $12 each or buying 8-packs of batteries for $15 each?

*Answer: *3 8-packs of batteries by $3

*Solution: *First, we need to find the total cost of buying the 24 batteries in each scenario. To make 24, we need to buy four 6-packs (6 × 4 = 24). One 6-pack of batteries cost $12, so four 6-packs of batteries cost $48 (12 × 4 = 48). To make 24, we need to buy three 8-packs (8 × 3 = 24). One 8-pack of batteries is $15, so three 8-packs of batteries is $45 (15 × 3 = 45). Since the four 6-packs of batteries cost $48 and the three 8-packs of batteries cost $45, the three 8-packs are a better buy because it is $3 cheaper.

**Middle School:**

*Question: *What was the original price of a pair of pants that was 15% off and its discounted price is $51?

*Answer: *$60

*Solution: *One formula for finding the discount price is (original price)(1 – percent discount) = (discount price). Since we are given what the discount price and the percent is, we can substitute these values into the formula to find the original cost.

(original cost)(1 – 0.15) = 51

Simplify the parenthesis.

(original cost)(0.85) = 51

Divide both sides by 0.85.

original cost = 60.

The original cost of the pair of pants is $60.

Another way of solving this problem is to find the whole given the percent and the part. Since it is 15% off, that means that the discounted price is 85% off of the original price. 85% of what number is 12. Let n be the number.

0.85n = 51

Divide both sides by 0.85.

n = 60.

The original cost of the pair of pants is $60.

**Algebra and Up:**

*Question: *The sum of 3 consecutive odd integers is –93. What are the three numbers?

*Answer: *–33, –31, –29

*Solution: *Let n be the first odd integer. The second number is the next odd integer, which can be found by adding 2 to the first term. So, the second term in n + 2. Similarly, the third term is found by adding 4 to the first term. So, the third term is n + 4. Adding all of these values together, we have that:

n + n + 2 + n + 4 = –93

Combine the like terms.

3n + 6 = –93

Subtract 6 from both sides.

3n = –99

Divide both sides by 3.

n = –33

So the first number is –33. This means that the second number is –31 and the third number is –29.