Exploring Calendars and
the Origins of April Fool’s Day

Early Childhood:

The first Saturday in April is Saturday, April 7th.  What is the date of the next Saturday in April?

Write down the dates of all of the Saturdays in April.

Describe the pattern of the dates that you’ve written down.

Looking at a calendar for April, describe any other patterns that you notice.


Upper Elementary:

In 1562 in France, the date of New Year’s Day was officially changed from April 1 to January 1st. Anyone who didn’t realize this switch was regarded as a fool .. thus April Fool’s Day!

How many years ago did this change take place?

How many months are there from January 1 to April 1?

How many days?

Explain how you solve these problems.

Middle School:

Calendar Magic:

Take any calendar. Tell someone to choose 4 days that form a square like the four squares below without telling you what is chosen:

calendar math exercise

Ask only for the sum of the four days. For this example, you would be told, “The sum is 72.”

How can you use algebra to figure this out for any 4 squares on a calendar? Practice and explain.

Website Resources:


Boston Marathon

The Boston Marathon, organized by the Boston Athletic Association, is the world's oldest marathon. It takes place on the third Monday in April, also known as Patriot's Day, which is a holiday (in Maine and Massachusetts) that commemorates the famous battles of Lexington and Concord. This year, the race will be run on April 16th, 2018.

Early Childhood:

Emily lives 23 miles from her grandmother's house. The length of the Boston Marathon is just over 26 miles long.

Which is longer - the distance to Emily's grandmother's house or the distance of the Boston Marathon? Write a number sentence comparing these two distances.

What is the difference in these two distances? Represent your solution on a number line diagram.


Upper Elementary:

$830,500 in prize money will be rewarded for the Boston Marathon in 2018, as well as an additional $220,000 in bonuses if records are broken in the open, masters, or wheelchair divisions.

Is this more or less than one million dollars? Explain how you know.

This year will be the 122 running of the Boston Marathon. In what year did the first race take place?

Middle School:

Jessica is training to run the Boston Marathon. She averages an 8.5 minute per mile pace. She would like to finish the 26.2 mile race in under 4 hours. Will she be able to do so at this pace? Show how you know.

If she starts the marathon at 11:15 in the morning, what is her estimated arrival time at the following points along the race:

Half-way point 13.1

Beginning of Heartbreak Hill - mile 20.5

The Finish Line - mile 26.2

The top male finisher in 2017 finished the marathon in 2 hours and 9 minutes. What was his pace per mile?

The top female finisher in 2017 finished the marathon in 2 hours and 21 minutes. What was her pace per mile?

Website Resources:


Cherry Blossoms

One of the most beautiful signs of spring is the blooming of cherry blossoms.

Over 100 years ago, in 1912, Japan presented the United States with a gift of 3,020 cherry blossom trees. In a special ceremony, the wife of the Japanese ambassador planted two Yoshino cherry trees that are still standing in Washington, DC today.

In many parts of the country, cherry blossom festivals are held to celebrate and appreciate the beauty of these trees.

Early Childhood

Suzi counted 15 cherry blossoms on her cherry blossom branch. She had 8 more blossoms than her friend Matthew.

How many cherry blossoms were on Matthew's branch?

Write a matching equation with a variable, and explain your solution.

Upper Elementary

“On a day in spring a boy has gathered a bouquet of cherry blossoms under a cherry tree. Nearby a poet is reading some of his poems aloud. As he reads, the boy counts out cherry blossoms, one blossom for each word of a poem. After a number of poems (haiku) each 17 words in length the boy has 3 blossoms remaining; after some 28- word poems the boy has 5 blossoms left; after some 31-word poems, he has 8 blossoms left. What is the least number of blossoms the boy has gathered?” Show and explain your thinking.

Source: MAA.org

Middle School

Cherry Blossom trees can grow up to 24 inches per year. If a cherry blossom tree is 16 feet tall, and has been steadily growing at this rate, approximately how old is the tree?

STRATEGY: Can you show your solution using a double number line?

Website Resources:


How To Use 'Same But Different Math'

Same But Different Math images are best used in the context of a number talk where children are gathered in a common space and know the routine of sharing thoughts and ideas. Teachers use talk moves to keep the dialogue going among and between students. The teacher’s role is to facilitate the conversation, allowing a forum for the sharing of important ideas.

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