1. Teacher Guide
This lesson is designed to teach kids to ask a critical thinking question that you can’t just put into a search box to solve. To do that, we encourage them with smaller questions that search can help them answer. Make sure that you read the notes for each slide: they not only give you teaching tips but also provide answers and hints so you can help the kids if they are having trouble.
Remember, you can always send feedback to the Bing in the Classroom team at You can learn more about the program at bing.com/classroom and follow the daily lessons on our Partners In Learning site.
Want to extend today’s lesson? Consider using Skype in the Classroom to arrange for your class to chat with another class in today’s location. And if you are using Windows 8, you can also use the Bing apps to learn more about this location and topic; the Travel and News apps in particular make great teaching tools.
Nell Bang-Jensen is a teacher and theater artist living in Philadelphia, PA. Her passion for arts education has led her to a variety of roles including developing curriculum for Philadelphia Young Playwrights and teaching at numerous theaters and schools around the city. She works with playwrights from ages four to ninety on developing new work and is especially interested in alternative literacies and theater for social change. A graduate of Swarthmore College, she currently works in the Artistic Department of the Wilma Theater and, in addition to teaching, is a freelance actor and dramaturg. In 2011, Nell was named a Thomas J. Watson Fellow and spent her fellowship year traveling to seven countries studying how people get their names.
This lesson is designed to teach the Common Core State Standard: Operations & Algebraic Thinking
CCSS.Math.Content.3.OA.B.5 Apply properties of operations as strategies to multiply and divide.2 Examples: If 6 × 4 = 24 is known, then 4 × 6 = 24 is also known. (Commutative property of multiplication.) 3 × 5 × 2 can be found by 3 × 5 = 15, then 15 × 2 = 30, or by 5 × 2 = 10, then 3 × 10 = 30. (Associative property of multiplication.) Knowing that 8 × 5 = 40 and 8 × 2 = 16, one can find 8 × 7 as 8 × (5 + 2) = (8 × 5) + (8 × 2) = = 56. (Distributive property.)
CCSS.Math.Content.3.OA.D.8 Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.3
CCSS.Math.Content.3.OA.D.9 Identify arithmetic patterns (including patterns in the addition table or multiplication table), and explain them using properties of operations. For example, observe that 4 times a number is always even, and explain why 4 times a number can be decomposed into two equal addends.

2. Although meerkats show some behavior that is similar to humans, they live much shorter lives. How much longer does the average human live than the average meerkat?
© Nico Smit/Rex Features
© Nico Smit/Rex Features
Having this up as kids come in is a great settle down activity. You can start class by asking them for thoughts about the picture or about ideas on how they could solve the question of the day.

3. Although meerkats show some behavior that is similar to humans, they live much shorter lives. How much longer does the average human live than the average meerkat?
A group of meerkats is called a “clan.” But other acceptable terms include “gang” and “mob,” which may seem more appropriate in this case. Our class clown is probably yawning or perhaps calling out to fellow members of the clan.
But it’s that kind of behavior, and our tendency to think of it in human terms, that makes meerkats so endearing. It’s also what prompts many field studies of these deeply social animals. With 20 to 30 meerkats in an average group, the individuals work together to ensure the safety and health of all members.
Depending on time, you can either have students read this silently to themselves, have one of them read out loud, or read it out loud yourself.

4. Although meerkats show some behavior that is similar to humans, they live much shorter lives. How much longer does the average human live than the average meerkat? 1
Thinking
Based on what you know about the lives of meerkats and the lives of humans, what is an informed estimate for what the difference between their average life expectancies might be? 2
Web Search
If we knew the life expectancy of the average human and the life expectancy of the average meerkat, what operation would we use to find the difference? 3
If we knew the life expectancy of the average human and the life expectancy of the average meerkat, how could we predict whether the difference between these numbers would be odd or even? 4
Image Search
Look up the average life expectancy of a meerkat and the average life expectancy of a human. Use an online visual representation to compare these different amounts. What would you estimate is the difference between them? 5
How could you write a formula to compare these average life expectancies, using letters standing in for the unknown numbers?
There are a couple of ways to use this slide, depending on how much technology you have in your classroom. You can have students find answers on their own, divide them into teams to have them do all the questions competitively, or have each team find the answer to a different question and then come back together. If you’re doing teams, it is often wise to assign them roles (one person typing, one person who is in charge of sharing back the answer, etc.)

5. Although meerkats show some behavior that is similar to humans, they live much shorter lives. How much longer does the average human live than the average meerkat? 5
Minutes
You can adjust this based on how much time you want to give kids. If a group isn’t able to answer in 5 minutes, you can give them the opportunity to update at the end of class or extend time.

6. Although meerkats show some behavior that is similar to humans, they live much shorter lives. How much longer does the average human live than the average meerkat? 1
Thinking
Based on what you know about the lives of meerkats and the lives of humans, what is an informed estimate for what the difference between their average life expectancies might be? 2
Web Search
If we knew the life expectancy of the average human and the life expectancy of the average meerkat, what operation would we use to find the difference? 3
If we knew the life expectancy of the average human and the life expectancy of the average meerkat, how could we predict whether the difference between these numbers would be odd or even? 4
Image Search
Look up the average life expectancy of a meerkat and the average life expectancy of a human. Use an online visual representation to compare these different amounts. What would you estimate is the difference between them? 5
How could you write a formula to compare these average life expectancies, using letters standing in for the unknown numbers?
You can ask the students verbally or let one of them come up and insert the answer or show how they got it. This way, you also have a record that you can keep as a class and share with parents, others.

7. Although meerkats show some behavior that is similar to humans, they live much shorter lives. How much longer does the average human live than the average meerkat? 1
Thinking
Based on what you know about the lives of meerkats and the lives of humans, what is an informed estimate for what the difference between their average life expectancies might be?
This is an opportunity for students to begin thinking about life expectancy from a biological perspective, as well as how they will go about solving this problem mathematically. In order to come up with an estimate, students should consider the different various threats to human life (for example, medical conditions) compared to the threats to meerkat life (for example, predators). Students may have a sense of how many years most humans live on average (around 80 years) and should guess what they think the average life of a meerkat is. Have them consider the average life expectancy of animals around a similar size (for example, a cat). As an example, if students guess meerkats live around 15 years, they can then solve for the difference between 80 and 15 years and come up with a difference of 65 (80 years – 15 years = 65 years). Answers will vary. This is a way for students to begin estimating what this difference might be; the exact numbers they use (and how accurate they are) is less important.

8. Although meerkats show some behavior that is similar to humans, they live much shorter lives. How much longer does the average human live than the average meerkat? 2
Web Search
If we knew the life expectancy of the average human and the life expectancy of the average meerkat, what operation would we use to find the difference?
(Possible queries: “math for kids, how to solve for difference”, “math for kids, knowing what operation to use”).
Students should think critically (and if necessary, use the Bing Search Bar to find resources to help them) and determine how they’ll solve for this difference in life expectancies. They should ultimately conclude that they’ll need to create an equation that uses subtraction. Students should think about how the key word here is difference. It may also help for them to use small numbers to think conceptually about it. (For example, if one average life expectancy was 10 years, and one was 1 year, how would you solve for the difference between them?)

9. Although meerkats show some behavior that is similar to humans, they live much shorter lives. How much longer does the average human live than the average meerkat? 3
Web Search
If we knew the life expectancy of the average human and the life expectancy of the average meerkat, how could we predict whether the difference between these numbers would be odd or even?
(Possible queries: “for kids, mathematical equations, even and odd numbers”, “for kids, even and odd numbers in equations”).
Students should think critically (and if necessary, use the Bing Search Bar to find resources to help them) to think about whether the answer they find will be odd or even. It may help them to think conceptually about it using small numbers and to experiment with different combinations. For example, students could try to solve the equation by plugging in the life expectancies of 10 years and 1 year and conclude that the difference would be an odd number. (In other words even – odd = odd). If you had two other life expectancies (9 years and 1 year), the difference would be even. (In other words, odd – odd = even). If you had 10 years and 2 years, the difference would be even (In other words, even – even = even). And finally, if you had 9 years and 2 years, the difference would be odd. (In other words, odd – even = odd). Students should test out these hypotheticals so that once they find the average life expectancy of humans and meerkats, they’re able to predict whether the difference will be odd or even.

10. Although meerkats show some behavior that is similar to humans, they live much shorter lives. How much longer does the average human live than the average meerkat? 4
Image Search
Look up the average life expectancy of a meerkat and the average life expectancy of a human. Use an online visual representation to compare these different amounts. What would you estimate is the difference between them?
(Possible queries: “average life expectancy of a human”, “average life expectancy of a meerkat”, “math for kids, interactive online bar graph”, “for kids, interactive bar graph online”).
The average life expectancy of a human in the United States is 79.8, or approximately 80 years (according to: The average life expectancy of a meerkat is about 13 years (according to Students should then find an interactive resource online that allows them to put these amounts into a visual model. For example, this website ( is a great resource. Students should select a “bar graph” and put in the numbers under “data” to find a visual representation of this difference and estimate what number it is.

11. Although meerkats show some behavior that is similar to humans, they live much shorter lives. How much longer does the average human live than the average meerkat? 5
Thinking
How could you write a formula to compare these average life expectancies, using letters standing in for the unknown numbers?
This is an opportunity for students to practice using letters to stand in for unknown numbers. After writing the equation, they should be sure to create a key for it that explains what each letter represents. They may start by mapping out (using words) what the equation should look like. For example:
Average life expectancy of human – average life expectancy of meerkat = difference in average life expectancies
They can then use letters to represent these amounts. For example:
H – M = X
H = Average Human Life Expectancy
M = Average Meerkat Life Expectancy
X = Difference in Average Life Expectancies

12. Although meerkats show some behavior that is similar to humans, they live much shorter lives. How much longer does the average human live than the average meerkat?
This slide is a chance to summarize the information from the previous slides to build your final answer to the question. At this point students should have found that the average life expectancy for a human is around 80 years old and the average life expectancy for a meerkat is around 13 years old. (Answers may vary). They can then plug these numbers into the equations they have developed. (They should also think before solving about whether the answer will be even or odd, based on the fact we are subtracting an odd number from an even number). Ultimately, they should conclude that the average human is expected to live approximately 67 years longer than the average meerkat.
80 years – 13 years = 67 years.