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Relative Sizes of Measurement Units

A 50-minute Grade 4 lesson on how big measurement units are compared with each other — feet and inches, pounds and ounces, gallons and quarts — and on writing a larger unit in a smaller one with a two-column table.

Relative Sizes of Measurement Units is a free 50-minute Grade 4 math lesson plan for Common Core standard 4.MD.A.1 — know how big units are compared with each other, and write a measurement in a larger unit as one in a smaller unit. It is timed across 5 sections, gives the exact wording to use where the wording carries the mathematics, names 3 misconceptions with the teaching move that addresses each, and ends with an exit ticket and a printable worksheet with its answer key.

Grade:
Grade 4
Length:
50 minutes
Standard:
4.MD.A.1

Grade 4 · Measurement & Data

4.MD.A.1

Know relative sizes of measurement units within one system of units including km, m, cm; kg, g; lb, oz.; l, ml; hr, min, sec. Within a single system of measurement, express measurements in a larger unit in terms of a smaller unit. Record measurement equivalents in a two-column table.

Objective

Students will be able to state how many of a smaller unit make one larger unit within a system, express a measurement in a larger unit in terms of a smaller unit, and record the equivalents in a two-column table.

Students are successful when they can

  • States the key facts: 1 ft = 12 in, 1 yd = 3 ft, 1 lb = 16 oz, 1 gal = 4 qt, 1 qt = 2 pt, 1 pt = 2 cups, 1 hr = 60 min, 1 kg = 1,000 g.
  • Completes a two-column table such as feet and inches by multiplying by the same number each row.
  • Compares two measures in different units, such as 2 ft and 20 in, by writing both in the smaller unit.

What you need

  • A yardstick, a 12-inch ruler and a measuring tape
  • A gallon jug, a quart, a pint and a measuring cup, with water to pour
  • A kitchen scale showing pounds and ounces
  • Blank two-column tables
  • The printable practice sheet linked at the end of this plan

The lesson

Warm-up — which is bigger?

6 min
  1. Hold up a ruler and a yardstick. Ask how many rulers fit along the yardstick. Lay them out: three.
  2. Ask whether a yardstick is 3 long or 36 long. Both, depending on the unit, and that is the lesson.

Teach — one big unit is many small ones

15 min
  1. State the facts while showing the objects: 1 foot is 12 inches; 1 yard is 3 feet, which is 36 inches.
  2. Pour water: a gallon fills 4 quarts, a quart fills 2 pints and a pint fills 2 cups. Write each fact as it is poured.
  3. Build a two-column table, feet and inches: 1 and 12, 2 and 24, 3 and 36, 4 and 48. Each row adds 12, because each foot is 12 more inches.
  4. Build pounds and ounces the same way: 1 and 16, 2 and 32, 3 and 48. Ask what rule takes the left column to the right: multiply by 16.
  5. Convert a mixed measure: 2 ft 5 in is 24 + 5 = 29 inches. Then 3 lb 4 oz is 48 + 4 = 52 ounces.
  6. Compare 2 feet and 20 inches. Write 2 feet as 24 inches; 24 > 20, so 2 feet is longer even though 2 < 20.
  7. Show the metric and time facts follow the same pattern: 1 km = 1,000 m, 1 m = 100 cm, 1 L = 1,000 mL, 1 hr = 60 min, 1 min = 60 sec.
“A bigger unit is made of many smaller units. To write it in the smaller unit, multiply by how many fit inside one. The number gets bigger because the unit got smaller.”

Guided practice — build the tables

14 min
  1. Pairs complete three two-column tables: yards and feet, gallons and quarts, and hours and minutes.
  2. They write the rule above each table, such as 'multiply by 4'.
  3. They then answer three comparisons, writing both measures in the smaller unit before choosing >, = or <.

Independent practice

12 min
  1. Students complete a customary conversions page.
  2. Answers that are multiples of 10 — 30 inches for 3 feet — are the metric habit applied to customary units and need the facts, not more arithmetic.

Close

3 min
  1. Ask which is more: 3 quarts or 5 pints.
  2. 3 quarts is 6 pints, so 3 quarts. Writing both in the smaller unit before comparing is the habit worth ending on.

What goes wrong, and why

Each of these is a reasoning error rather than carelessness. The fix addresses the reasoning.

Converts 3 feet to 30 inches.

Why: Metric conversions and place value both go in tens, so multiplying by 10 has become the default way to change a unit.

Fix: Lay three rulers along a yardstick and count the inches. Then state the fact first in writing — 1 ft = 12 in — before any conversion, so the multiplier comes from the units, not from habit.

Says 20 inches is longer than 2 feet because 20 is bigger than 2.

Why: The numbers are being compared and the units ignored, because comparing numbers has always been enough until now.

Fix: Write both measures in the same unit before comparing. 2 feet is 24 inches, and 24 inches against 20 inches is a comparison of numbers again.

Writes 2 ft 5 in as 25 inches.

Why: The two numbers have been placed side by side as digits, because '2 and 5' reads like 25 in place value.

Fix: Convert the feet first and add the inches: 2 ft is 24 in, and 24 + 5 = 29 in. A two-column table with a row for 2 feet makes the 24 visible.

If they are not there yet

  • Work with one system at a time — length first — with the measuring tools on the table.
  • Provide tables with the first two rows filled in, so the rule can be found before it is used.

If they finish early

  • Convert 2 gallons all the way to cups, writing each step: quarts, then pints, then cups.
  • Make a two-column table for minutes and seconds and use it to find how many seconds are in 4 1/2 minutes.
  • Explain why the number goes up when converting to a smaller unit, using two different systems as examples.

Exit ticket

Complete the table: yards and feet for 1, 2, 3 and 4 yards. Then: which is heavier, 2 pounds or 30 ounces?

What to look for: 3, 6, 9 and 12 feet; 2 pounds is 32 ounces, so 2 pounds is heavier. A table of 10, 20, 30, 40 means the metric habit is in charge; choosing 30 ounces means numbers were compared without converting.

Printable practice for 4.MD.A.1

Free to print and copy, answer key included. Each sheet can generate a fresh set of problems for a retake.

Questions about Relative Sizes of Measurement Units

How long does the Relative Sizes of Measurement Units lesson take?

50 minutes, split across 5 timed sections: warm-up 6 min, teach 15 min, guided practice 14 min, independent practice 12 min, close 3 min. The minutes are stated per section and add up to the stated length, so the plan can be cut or extended at a section boundary rather than abandoned halfway.

Which standard does Relative Sizes of Measurement Units teach?

CCSS.MATH.CONTENT.4.MD.A.1 — 4.MD.A.1, Measurement & Data for Grade 4: “Know relative sizes of measurement units within one system of units including km, m, cm; kg, g; lb, oz.; l, ml; hr, min, sec. Within a single system of measurement, express measurements in a larger unit in terms of a smaller unit. Record measurement equivalents in a two-column table.” In plain terms, know how big units are compared with each other, and write a measurement in a larger unit as one in a smaller unit.

What do I need to teach this lesson?

A yardstick, a 12-inch ruler and a measuring tape, a gallon jug, a quart, a pint and a measuring cup, with water to pour, a kitchen scale showing pounds and ounces, blank two-column tables and the printable practice sheet linked at the end of this plan. Everything listed is either ordinary classroom equipment or a free printable from this site — there is nothing to buy and nothing to prepare beyond photocopying.

What mistakes should I expect in this lesson?

Three, each a reasoning error rather than carelessness: converts 3 feet to 30 inches; says 20 inches is longer than 2 feet because 20 is bigger than 2 and writes 2 ft 5 in as 25 inches. The plan gives the thinking behind each one and the teaching move that addresses the thinking rather than the symptom.

How do I know whether the lesson worked?

The exit ticket asks: “Complete the table: yards and feet for 1, 2, 3 and 4 yards. Then: which is heavier, 2 pounds or 30 ounces?.” 3, 6, 9 and 12 feet; 2 pounds is 32 ounces, so 2 pounds is heavier. A table of 10, 20, 30, 40 means the metric habit is in charge; choosing 30 ounces means numbers were compared without converting. That tells you whether the class needs a reteach or a thirty-second conversation before you plan tomorrow.

Is there a worksheet to go with Relative Sizes of Measurement Units?

Yes — 1 printable 4.MD.A.1 worksheet, linked at the end of the plan and free like the rest of the site. Each one comes with an answer key and 25 versions, so the practice after the lesson can be a different paper on every desk.

Is Relative Sizes of Measurement Units free to use?

Yes. The plan, its printables and their answer keys are free to read, print and photocopy for your own class, with no account and no email capture. It was last reviewed on October 22, 2026. Please do not resell it or republish it as your own.

Last reviewed 2026-10-22. Aligned to 4.MD.A.1 of the Common Core State Standards for Mathematics.