Worksheet Grade 4 Math
Riverside Elementary's Rain Barrel: Liters, Milliliters, and Minutes
A grade 4 worksheet using a school rain barrel to practice converting liters to milliliters and hours to minutes, plus multi-digit multiplication of collection totals.
Objectives
- Students will complete a two-column table converting liters to milliliters and hours to minutes.
- Students will multiply multi-digit numbers to find total rainwater collected over several days.
- Students will explain why converting to a smaller unit produces a larger number for the same amount of water.
Teacher overview
The science club at Riverside Elementary set up a rain barrel under a gutter downspout to collect water for the school's vegetable garden. The club measures the barrel's contents in liters and tracks how long it takes to fill during a storm in hours, which gives this worksheet a natural reason to practice two measurement conversions at once: liters to milliliters and hours to minutes. Multiplying the barrel's daily collection rate by a number of rainy days also gives students practice with multi-digit multiplication in a context with a real total to check their work against.
A common misconception to watch for: students sometimes think converting a measurement to a smaller unit changes the actual amount of water, when only the number and the unit change, not the quantity itself. Item 9 asks students to explain this directly.
Student Worksheet
Use these facts for every problem below. One liter equals 1,000 milliliters. One hour equals 60 minutes. The rain barrel holds 200 liters when it is full.
Complete the two-column table below. Convert each amount of water from liters to milliliters.
Liters (L) Milliliters (mL) 1 5 10 50 200 Look at your completed table. How many milliliters of water are in the full barrel?
On a rainy day, the barrel collects 14 liters of water. April had 12 rainy days. How many liters did the barrel collect that month?
Take your answer to item 3. Convert it to milliliters.
One storm fills the barrel all the way in 3 hours. How many minutes is that?
Complete a second two-column table. Convert each amount of time from hours to minutes.
Hours (hr) Minutes (min) 1 2 4 6 The garden's drip watering system runs for 45 minutes every day. How many minutes does it run over 5 days?
The barrel starts full at 200 liters. The science club uses 25 liters each day for the garden. How many liters are left after 4 days?
A classmate thinks that 168 liters changed to milliliters should give a smaller number. She says, "Milliliters sound tiny." Explain what is wrong with her idea. Use the word "unit" in your answer.
A class next door wants to fill an empty 350-liter barrel. They will use only a 1-liter jug, one pour at a time. How many jugs of water would they need?
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Answer Key
Answer: 200,000 mL (full table: 1,000 mL, 5,000 mL, 10,000 mL, 50,000 mL, 200,000 mL).
Each value is found by multiplying the number of liters by 1,000, since 1 L = 1,000 mL.Answer: 200,000 mL.
Read directly from the completed table: 200 liters equals 200,000 milliliters.Answer: 168 liters.
14 liters per rainy day × 12 rainy days = 168 liters. Students may show this as an area model splitting 12 into 10 + 2: (14 × 10) + (14 × 2) = 140 + 28 = 168.Answer: 168,000 mL.
168 liters × 1,000 mL per liter = 168,000 milliliters.Answer: 180 minutes.
3 hours × 60 minutes per hour = 180 minutes.Answer: 360 min (full table: 60 min, 120 min, 240 min, 360 min).
Each value is found by multiplying the number of hours by 60, since 1 hr = 60 min.Answer: 225 minutes.
45 minutes per day × 5 days = 225 minutes.Answer: 100 liters.
25 liters per day × 4 days = 100 liters used. 200 liters − 100 liters = 100 liters remaining.Answer: The classmate is incorrect.
Milliliters are a much smaller unit than liters, so it takes many more of them to equal the same amount of water. Converting to a smaller unit always produces a larger number for the same quantity, because the unit is smaller, not because there is more water. A strong answer names both that the amount of water stays the same and that the unit size explains the bigger number.Answer: 350 jugs.
Each 1-liter jug adds exactly 1 liter, so filling a 350-liter barrel one jug at a time takes 350 jugs.
Differentiation
Support (below grade level)
Provide a printed reference card showing "L → mL: multiply by 1,000" and "hr → min: multiply by 60" for students to keep beside their work, and complete the first row of each table together as a class before students finish the rest independently.
Extension (above grade level)
Ask students to figure out how many seconds the 3-hour storm in item 5 lasted, requiring a second conversion step (hours to minutes, then minutes to seconds), and to explain which unit, hours or seconds, would be the less practical choice for a weather report and why.
ELL supports
Pre-teach liter, milliliter, convert, and total with a labeled picture of a liter bottle next to 1,000 milliliter markings. Allow students to show their multiplication using an area model or drawn array instead of a written equation for items 3 and 7.