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Aquarium Care: Variable Plans worksheet preview

Worksheet

Aquarium Care: Variable Plans

Model aquarium feeding and tank-care situations with variables, including unknown amounts and quantities that can change.

Grade 6MathInteractive · Printable

Aligned to6.EE.B.6

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What’s included

  • Single worksheet
  • Auto-graded online
  • 1 Common Core standard
  • Printable answer key
  • 14 questions
  • Classroom-ready

Details

Format
Interactive · Printable
Grade
Grade 6
Subject
Math
Question types
Multiple choice, Matching, Circle the answer, Short answer

About this worksheet

What students practice

  • Students use variables to represent unknown quantities and quantities that can vary.
  • Students choose and write expressions that model aquarium feeding and tank-care situations.
  • Students distinguish expressions for equal groups, shared amounts, and remaining quantities.

How to use

Use after introducing variables and numerical expressions. Have students identify what each variable represents before choosing a model, then discuss the final error analysis.

Curriculum

Common Core standard covered

6.EE.B.6

Use a variable to stand for an unknown or any number in a set, and write expressions for real-world problems.

Preview

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Name Date

Aquarium Care: Variable Plans

Use variables to describe tank care and feeding schedules.

Define the Variable

Read each situation independently. Choose or match the variable model that fits.

1.
An aquarium keeper records an unknown number of fish in a tank. Which definition lets n represent that unknown quantity?
  • A. n is the number of liters in the tank.
  • B. n is the number of fish in the tank.
  • C. n is the number of tanks in the room.
  • D. n is the number of minutes until feeding.
2.
Each tank receives 3 feeding checks per day. The aquarium may have 4, 5, or 6 tanks open to visitors. Let n represent the number of open tanks. Which statement is true?
  • A. n must equal 6 because 6 is the largest choice.
  • B. n can equal 4, 5, or 6, depending on the day.
  • C. n must equal 15 because 4 + 5 + 6 = 15.
  • D. n must equal 3 because there are 3 checks.
3.
Priya has measured x grams of fish food. She measures 7 more grams into the same container. Which expression represents the total grams of food?
  • A. 7 − x
  • B. 7x
  • C. x + 7
  • D. x − 7
4.
For each situation, x is the number of grams of food in a container at the start. Match the situation to an expression for the grams of food afterward.
  1. Use 8 grams to feed the fish.
  2. Add 8 grams from a refill bag.
  3. Divide all the food equally among 8 cups. Find the amount in one cup.
  4. Combine 8 containers that each hold x grams.
  1. A. x + 8
  2. B. x − 8
  3. C. 8x
  4. D. x ÷ 8
5.
A keeper may prepare feeding portions for 2, 4, or 6 tanks. Let n be the number of tanks. Each tank needs 5 grams of food. Select every expression that represents the total grams needed for any allowed value of n.

5 + n5nn ÷ 5n × 5

Model the Care Plan

Choose an expression for each quantity. Keep track of what happens first.

6.
Omar starts with 48 grams of food and uses x grams during the morning feeding. Which expression represents the grams left?
  • A. x − 48
  • B. 48 + x
  • C. 48 − x
  • D. 48 ÷ x
7.
For a partial water change, a keeper prepares x liters of water and divides it equally among 6 tanks. Which expression represents the liters added to each tank?
  • A. 6 ÷ x
  • B. 6x
  • C. x − 6
  • D. x ÷ 6
8.
The table shows a feeding plan. Let n be the number of tanks. Which expression represents the total grams of food prepared?
Daily Food Preparation
Number of tanksTotal food (g)
215
427
745
The keeper prepares 6 grams per tank, plus 3 extra grams in a separate reserve cup.
  • A. 6n + 3
  • B. 9n
  • C. 6(n + 3)
  • D. 3n + 6
9.
Lena has n tanks to inspect. She finishes inspecting 2 tanks. Each remaining tank takes 4 minutes to inspect. Which expression represents the minutes needed to inspect all the remaining tanks?
  • A. 4(n − 2)
  • B. 4n − 2
  • C. 4(n + 2)
  • D. n − 2 × 4
10.
A feeding period starts x minutes after noon and lasts 12 minutes. Which expression represents how many minutes after noon the feeding period ends?
  • A. x − 12
  • B. x + 12
  • C. 12x
  • D. 12 − x

Check and Create Models

Use the meaning of each variable to check the model. Explain your reasoning in the final question.

11.
A keeper removes x liters of water from a tank that contains 70 liters, then adds 9 liters of clean water. Which expression represents the liters in the tank afterward?
  • A. 70x + 9
  • B. 70 + x − 9
  • C. 70 − (x + 9)
  • D. 70 − x + 9
12.
The expression 2x + 5 represents a care plan. Select every situation that this expression models.

Prepare 2 grams of food for each of x tanks, plus 5 grams in reserve.Prepare 2 grams of food for each of x tanks and each of 5 additional tanks.Complete two checks that each take x minutes, then spend 5 minutes recording notes.Divide x grams of food between 2 containers, then add 5 grams to one container. Find the amount in that container.

13.
A feeder starts with 90 grams of food. It releases 6 grams at each feeding. Let n be the number of completed feedings. Which expression represents the grams remaining?
  • A. 90 − 6n
  • B. 6n − 90
  • C. 90 − 6 − n
  • D. (90 − 6)n
14.
A keeper has x grams of food. She sets aside 10 grams for a special tank, then divides the rest equally among 3 other tanks. Mateo writes x ÷ 3 − 10 for the grams each of those 3 tanks receives. Write a correct expression and explain why Mateo's expression does not match the plan.

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