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Classroom activity Grade 5 Math

Merrowdale Lab Sample Splits: A Grade 5 Fraction Card Game

A grade 5 card game where teams match division sentences, models, and answers for a fictional lab that pours culture jars into small bottles and trays.

Objectives

  1. Students will divide a whole number of liters by a unit fraction to count small containers.
  2. Students will divide a unit fraction by a whole number to find an equal share.
  3. Students will explain why dividing by a unit fraction gives an answer greater than the starting number.

Vocabulary

Key words: unit fraction, culture, liter, tray, divide

Teacher overview

This is a matching card game for teams of three or four, set in the fictional town of Merrowdale, whose water lab keeps jars of helpful microbes that the treatment plant adds to its tanks to break down waste. Technicians spend part of every day pouring from a large jar into small bottles or spreading a small amount evenly across a row of trays, so the same two questions come up again and again: how many small containers a jar will fill, and how much goes into each tray when one small amount is shared. The game gives each of those questions its own round, so students meet both directions of unit-fraction division without blurring them together. The misconception it targets is the belief that dividing always makes a number smaller, which leads students to answer that 4 liters poured into half-liter bottles fills 2 bottles.

Activity Directions

  1. Before class, print two decks for each group. The round-one deck has six sentence cards reading 4 divided by 1/2, 3 divided by 1/4, 5 divided by 1/3, 6 divided by 1/5, 2 divided by 1/6, and 8 divided by 1/2, plus six matching answer cards reading 8, 12, 15, 30, 12, and 16, plus six picture cards showing a jar cut into the matching small containers. The round-two deck has six sentence cards reading 1/2 divided by 3, 1/4 divided by 6, 1/3 divided by 4, 1/2 divided by 5, 1/5 divided by 2, and 1/4 divided by 3, plus six answer cards reading 1/6, 1/24, 1/12, 1/10, 1/10, and 1/12, plus six picture cards.
  2. Set the scene (6 min): Explain what the Merrowdale lab does and hold up a container to stand in for a one-liter jar. State the rule of the two rounds: in round one a big jar is poured into small bottles, and in round two one small amount is shared evenly among trays.
  3. Teach the rules (4 min): Deal one deck face up in the middle of each team's table. A team's job is to build six sets of three cards, one sentence, one picture, and one answer. Teams may use fraction strips to check any set before they commit to it.
  4. Round one (8 min): Teams build the six sets from the round-one deck. Stop play at 8 minutes and have each team read one completed set aloud. Two sentences in this deck share the same answer card, so the picture is what decides which set each copy belongs to. A set is worth one point only if the picture matches the sentence as well as the answer does.
  5. Round two (8 min): Collect the first deck, hand out the second, and repeat with the sharing sentences. Two of the answers in this deck appear on two cards each, so teams must decide which sentence goes with which copy.
  6. Handout (5 min): Students complete handout questions 1 through 8 at their seats, working alone.
  7. Debrief (4 min): Ask one team to explain why the round-one answers were all larger than the starting number while the round-two answers were all smaller. Record one sentence from each round side by side on the board so the class can compare what is being divided by what.
Merrowdale Lab Sample Splits: A Grade 5 Fraction Card Game — Grade 5 Math
Name: ____________________________ Date: ______________

Student Handout

The Merrowdale lab pours culture from large jars into small bottles and trays. Answer each question and show the division sentence you used.

  1. A jar holds 4 liters. Technicians pour it into bottles that each hold 1/2 liter. How many bottles do they fill?
  2. A jar holds 3 liters. Technicians pour it into bottles that each hold 1/4 liter. How many bottles do they fill?
  3. A jar holds 5 liters. Technicians pour it into bottles that each hold 1/3 liter. How many bottles do they fill?
  4. A technician spreads 1/2 liter of culture evenly across 3 trays. How much goes in each tray?
  5. A technician spreads 1/4 liter of culture evenly across 6 trays. How much goes in each tray?
  6. A technician spreads 1/3 liter of culture evenly across 4 trays. How much goes in each tray?
  7. A jar holds 6 liters. Technicians pour it into bottles that each hold 1/5 liter. How many bottles do they fill?
  8. Starting with 2 liters, do technicians fill more 1/2-liter bottles or more 1/4-liter bottles?

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key
  1. Answer: 8 bottles.
    Each liter fills 2 half-liter bottles, so 4 liters fill 4 x 2 = 8 bottles. Written as division, 4 divided by 1/2 = 8.
  2. Answer: 12 bottles.
    Each liter fills 4 quarter-liter bottles, so 3 liters fill 3 x 4 = 12 bottles. Written as division, 3 divided by 1/4 = 12.
  3. Answer: 15 bottles.
    Each liter fills 3 third-liter bottles, so 5 liters fill 5 x 3 = 15 bottles. Written as division, 5 divided by 1/3 = 15.
  4. Answer: 1/6 liter.
    Splitting one half into 3 equal parts gives sixths, so 1/2 divided by 3 = 1/6 liter in each tray.
  5. Answer: 1/24 liter.
    Splitting one fourth into 6 equal parts gives twenty-fourths, so 1/4 divided by 6 = 1/24 liter in each tray.
  6. Answer: 1/12 liter.
    Splitting one third into 4 equal parts gives twelfths, so 1/3 divided by 4 = 1/12 liter in each tray.
  7. Answer: 30 bottles.
    Each liter fills 5 fifth-liter bottles, so 6 liters fill 6 x 5 = 30 bottles. Written as division, 6 divided by 1/5 = 30.
  8. Answer: More 1/4-liter bottles.
    From 2 liters the lab fills 4 half-liter bottles but 8 quarter-liter bottles, because the smaller a bottle is, the more of them a jar will fill.

Differentiation

Support

Give these teams only the round-one deck and add a fourth card to each set showing the matching multiplication, such as 4 x 2 for the sentence 4 divided by 1/2. Let students pour water or dry rice from a one-liter container into half-liter and quarter-liter cups at a side table so the count comes from something they can see before they match cards.

Extension

Ask these teams to write two new sets of three cards, one for each round: one round-one set whose answer is 24, and one round-two set whose answer is 1/20. Have them trade the new cards with another team, who must check both sets and correct any picture that does not match.

ELL supports

Label a real one-liter bottle, a half-liter cup, and a quarter-liter cup and set them where every team can see them, with the words "jar," "bottle," "tray," and "share" written in English and, where possible, in students' home languages. Provide a sentence frame for the debrief: "In round one the answers grew because each bottle held ___ than a liter."

Extensions

Have students plan a set of samples for a fictional school science fair project on pond water. Given 2 liters of pond water and sample cups that each hold one eighth of a liter, they find how many cups they can fill, then find how many whole cups each of six team members would get and how many cups would be left over.