Lower Elementary:
Question: Kevin is in line to get his food from a deli. His order number is 73. If they are on order 59, how many people must Kevin wait for before he gets his food?
Answer: 14 people
Solution: To see how many people Kevin has to wait for, subtract the number they are on from his order number. 73 – 59 = 73 – 60 + 1 (we add one because when changing 59 to 60, we are subtracting one more, so we need to add one more)= 13 + 1 = 14
Upper Elementary:
Question: Anthony needs to fundraise $52.50 for his soccer team and $37.50 for his dance club. To do this, he is going to wash cars. If he gets $7.50 per car, how many cars does Anthony have to wash to reach his fundraising goals?
Answer: 12 cars
Solution: First, find the total amount Anthony needs to fundraise. $52.50 + $37.50 = $90. Then divide $90 by $7.50. Notice that if he makes $7.50 for one car, that means he makes $15 for two cars. 90/15 = 6 so he has to wash 6 sets of two cars, or a total of 12 cars, to make his goal.
Middle School:
Question: What is the smallest number greater than 1 that is not divisible by 2, 3, or 5 and is not a prime number?
Answer: 49
Solution: A prime number has only two factors, 1 and itself. So we need to find the smallest number that is not prime and does not have 2, 3, or 5 as prime factors. Recall that every number can be composed as a product of prime numbers (prime factorization). If we continue the list of prime factors, the next one is 7. Since 7 is the smallest prime number after 2, 3, and 5, if we multiply 7 times itself, we will get the smallest number that is not divisible by 2, 3, or 5 (since none of them are prime factors of 7) and that is not prime since its prime factors are 7 and 7. 7 × 7 = 49, so 49 is the smallest number greater than 1 that is not divisible by 2, 3, or 5 and is not prime.
Algebra and Up:
Question: What is the probability of drawing a queen or a heart in a standard deck of 52 cards?
Answer: 4/13
Solution: The total number of queens in the deck are 4. The total number of hearts is 13. If we add these together, we get 17 cards. However, we added the queen of hearts twice (since it satisfied both conditions). So we need to subtract one from this total so we do not double count the queen of hearts. So the total number of hearts and queens is 16 cards. The probability is 16/52, which reduces to 4/13.
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