Center for Mathematical Professional Learning and Educational Technology

Ichiro Problem

Ichiro Problem

Grade: 3-12

It has been one month since Ichiro’s mother has entered the hospital. Ichiro decided to pray with his younger brother at a local temple every morning so that she will get better soon. There are 18 ten-yen coins in Ichiro’s wallet and just 22 five-yen coins in the younger brother’s wallet. They decided to take one coin from each wallet every day, put them in the offertory box, and continue to pray until either wallet becomes empty. One day when they were done with their prayer, they looked into each other’s wallets. The amount of money in the younger brother’s wallet was greater than Ichiro’s amount of money. When this happened, how many days had it been since they started their prayers?

Fun at the Fair

Fun at the Fair

Grade: 3-5

Mrs. Hoffmann brings her 6 children to the fair. She buys a big box of 45 mini- donuts for the children to share equally. How many mini-donuts will each child get?

The children are ready to go on the fair rides! Mrs. Hoffmann buys a bag of 45 ride tokens for the children to share equally. If each ride costs one token, how many rides can each child enjoy?

Eucalyptus

Eucalyptus

Grade: 3-8

99% of the trees in our neighborhood are eucalyptus trees. The town planning commission wants to get rid of some of these trees because they spread too quickly. However, the people in my neighborhood like the trees. The commission argues that their new eucalyptus tree removal plan will cut down so few eucalyptus trees that 98% of the trees in our neighborhood will be eucalyptus trees. If the plan only involves removing eucalyptus trees, what percent of the existing tress in my neighborhood would the plan remove?

Carlos’ Cell Phone

Carlos’ Cell Phone

Grade: 3-12

Carlos is thinking of changing cell phone plans so he is comparing several different plans.

  • Plan 1) Pay as you go plan $0.99
  • Plan 2) Per minute $30 monthly fee plus $0.45
  • Plan 3) Per minute $40 monthly fee plus $0.35
  • Plan 4) Per minute $60 monthly fee plus $0.20
  • Plan 5) Per minute $100 monthly fee for unlimited minutes

What will Carlos need to consider to make his decision? How can Carlos figure out which plan is best for him?

Buying MP3s

Buying MP3s

Grade: 3-12

You have decided to use your allowance to buy an mp3 purchase plan. Your friend Alex is a member of i sound and pays $1 for each download. Another one of your friends, Taylor, belongs to Rhaps and pays $13 a month for an unlimited number of downloads. A third friend, Chris, belongs to e-musical and pays a $4 monthly membership fee and $0.40 a month per download. Each friend is trying to convince you to join their membership plan. Under what circumstances would you choose each of these plans and why?

Bundle of Books

Bundle of Books

Grade: 3-5

Nate’s grandma bought him 4 new books to read. She spent $38, and each book cost the same amount of money. Nate wants to return one of the books to the store. How much money will he get back?

Nate is a fast reader! He can read 4 books in one hour. If he has 38 books to read, how many hours will it take him to read them all?

Bucket of Trouble

Bucket of Trouble

Grade: 3-8

The ceiling of Betty’s kitchen has a leak. She hears 10 drips of water in 15 seconds. She puts a bucket under the leak and frantically calls the plumber. The plumber can’t be there for 5 hours. Will Betty need to empty the bucket? How much water will she waste?

Bubble Gum

Bubble Gum

Grade: 3-8

Have you ever wondered why gum loses its sweetness so quickly? Does it seem like the gum gets smaller after you chew it? Well, sugar contributes to gum’s flavor. During chewing, the sugar is lost, which makes the gum get smaller as it loses sweetness.

Birthday Balloon Bash

Birthday Balloon Bash

Grade: 3-8

Mr. Al Gebra’s class wanted to surprise him on his birthday by filling his classroom
with inflated balloons. How many balloons did they need?

Bicycles and Tricycles

Bicycles and Tricycles

Grade: 3-12

Jenny’s Bicycle Shop sells only bicycles and tricycles. They have a total of 24 seats and 61 wheels in the shop.

How many bicycles and how many tricycles are in the shop?