Metric unit of length worksheet for students to practice selecting appropriate units for measuring different objects.

Let’s go through each question one by one. We’ll use the reference chart at the top to help us pick the best unit for each item.

Remember:
- Millimeter (mm) = very small, like thickness of a credit card
- Centimeter (cm) = about width of your pinky finger; pencil metal part is ~1 cm
- Meter (m) = from floor to door knob (~1 m)
- Kilometer (km) = long distances, like roads

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1) Bug

A bug is small — not as big as a ruler (30 cm), but bigger than a millimeter. A ladybug is usually around 5–7 mm or maybe up to 1 cm. Looking at options:

A. 30 cm → too big (that’s a ruler!)
B. 5 cm → still too big for most bugs
C. 10 cm → way too big
D. 7 millimeters → yes! That’s reasonable for a small bug like a ladybug.

✔ Best answer: D. 7 millimeters

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2) Battery

Think of a AA battery — it’s about 5 cm tall. Let’s check:

A. 60 cm → that’s almost 2 feet — too tall
B. 2 meters → no way!
C. 5 centimeters → perfect for a standard battery
D. 3 kilometers → ridiculous

✔ Best answer: C. 5 centimeters

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3) Dresser

A dresser is furniture — you stand next to it. It’s probably around waist height or a bit higher. Waist height is about 1 meter, so dressers are often 80–100 cm tall.

Options:

A. 3 meters → that’s ceiling height — too tall
B. 30 cm → that’s knee height — too short
C. 45 cm → still too short
D. 90 cm → yes! About 3 feet — perfect for a dresser

✔ Best answer: D. 90 centimeters

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4) Refrigerator

Fridges are tall appliances — usually around 1.5 to 1.8 meters tall.

Options:

A. 5 km → nope
B. 180 centimeters → that’s 1.8 meters — perfect!
C. 30 cm → tiny fridge? No.
D. 4 meters → taller than most rooms!

✔ Best answer: B. 180 centimeters

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5) Lollipop

Lollipops on sticks — the stick is maybe 10–15 cm, and the candy adds a little more. Total length maybe 15–20 cm? But let’s see options:

A. 10 centimeters → possible, but maybe a bit short
B. 2 km → no
C. 30 millimeters → that’s 3 cm — too short
D. 30 centimeters → that’s 1 foot — might be a bit long, but some lollipops have long sticks

Wait — actually, typical lollipop stick is about 10–15 cm. The whole thing including candy might be 15–20 cm. So 30 cm seems too long.

But look again — option A is 10 cm. Maybe that’s just the stick? Or maybe they mean total?

Actually, many lollipops sold in stores are about 15–20 cm total. But since 10 cm is an option and 30 cm is too long, perhaps 10 cm is intended? Wait — let me think differently.

The image shows a lollipop with a stick — if we measure from bottom of stick to top of candy, it’s likely around 15–20 cm. But none of the options say that.

Option D is 30 cm — that’s 1 foot. Some giant lollipops exist, but not typical.

Option A: 10 cm — that’s 4 inches — possible for a small one.

Wait — maybe I should consider what’s most reasonable. Actually, looking back at the reference: “ruler is about 30 cm” — so 30 cm is a full ruler. A lollipop is shorter than a ruler.

So 10 cm is too short? Hmm.

Actually, let’s compare to pen later — pens are around 15 cm. Lollipop stick is similar to pen length? Maybe.

But here’s a better approach: eliminate impossible ones.

B and C are clearly wrong.

Between A (10 cm) and D (30 cm) — 30 cm is too long for a normal lollipop. 10 cm is a bit short but possible.

Wait — maybe the question means the diameter of the candy? No, the line goes along the whole thing — stick + candy.

I think the intended answer is A. 10 centimeters, assuming a small lollipop.

But let me double-check with real life: average lollipop stick is 10–15 cm. Candy adds 2–3 cm. So total 12–18 cm. Closest option is A (10 cm) or D (30 cm). Neither is perfect, but 10 cm is closer than 30 cm.

Actually, wait — maybe I made a mistake. Let’s look at question 8: Pen — options include 12 cm and 15 cm. Pens are about 15 cm. Lollipop stick is similar to pen length? Then total lollipop would be longer than pen? Not necessarily — candy is round, doesn’t add much length.

Perhaps 10 cm is acceptable.

But let’s hold off and come back after doing others.

Actually, let’s look at the image description mentally: the lollipop has a stick and a round candy. The measurement line goes from bottom of stick to top of candy. In reality, that’s about 15–20 cm. Since 15 isn’t an option, and 10 is too short, 30 is too long... this is tricky.

Wait — option C is 30 millimeters = 3 cm — definitely too short.

Maybe the test expects 10 cm? Or perhaps I’m overthinking.

Another idea: maybe “lollipop” refers only to the candy part? But the line includes the stick.

Looking at common educational materials, they often say lollipop is about 10–15 cm. Given the choices, A. 10 centimeters is the least unreasonable.

But let’s check online quickly in my mind: standard lollipop stick is 10 cm, candy adds 2–3 cm, so total 12–13 cm. Still, 10 cm is closest among given options? No, 30 cm is farther.

Actually, 10 cm is 100 mm, 30 cm is 300 mm. Real length ~150 mm. So 10 cm is 50 mm off, 30 cm is 150 mm off. So 10 cm is closer.

But there’s no 15 cm option. Perhaps the answer is A.

Wait — let’s see question 7: toothbrush — options include 17 cm, which is realistic. So maybe for lollipop, they expect 10 cm? I think I’ll go with A for now.

Actually, let’s skip and come back.

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6) Can of Beans

Standard can of beans is about 10–12 cm tall.

Options:

A. 10 centimeters → perfect
B. 120 centimeters → 1.2 meters — too tall
C. 2 km → no
D. 2 meters → no

✔ Best answer: A. 10 centimeters

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7) Toothbrush

Toothbrushes are usually 15–20 cm long.

Options:

A. 10 cm → a bit short
B. 3 meters → no
C. 17 centimeters → yes! Perfect
D. 1 meter → no

✔ Best answer: C. 17 centimeters

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8) Pen

Pens are typically 14–15 cm long.

Options:

A. 30 cm → too long (ruler size)
B. 5 meters → no
C. 12 centimeters → a bit short, but possible for short pens
D. 30 millimeters = 3 cm → too short

Most standard pens are 14–15 cm. 12 cm is close, but let’s see — option C is 12 cm, which is reasonable for some pens. Is there a better option?

Wait, 12 cm is 120 mm — actual pen is about 140–150 mm. So 12 cm is a bit short, but among options, it’s the best.

Option A is 30 cm — too long.

So C. 12 centimeters is the best available.

But let’s confirm: some pens are 12 cm, especially compact ones. Standard ballpoint is 14–15 cm, but since 15 isn’t an option, 12 is closest.

Actually, wait — option D is 30 mm = 3 cm — no.

So yes, C. 12 centimeters

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9) Ferris Wheel

Ferris wheels are huge — tens of meters tall. Small ones might be 20–30 m, large ones 50–100 m.

Options:

A. 23 meters → possible for a small ferris wheel
B. 50 kilometers → that’s city-sized — no
C. 30 centimeters → toy size — no
D. 5 meters → too small for a ride

So between A and B — 50 km is absurd. 23 meters is reasonable for a small amusement park ferris wheel.

For example, the London Eye is 135 m, but smaller ones exist. 23 m is about 75 feet — plausible.

✔ Best answer: A. 23 meters

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Now back to 5) Lollipop

We have options: A. 10 cm, B. 2 km, C. 30 mm, D. 30 cm

Realistic length: 15–20 cm

Closest option: A. 10 cm (off by 5–10 cm) vs D. 30 cm (off by 10–15 cm)

10 cm is closer numerically, but 30 cm is twice as far.

However, in educational contexts, sometimes they approximate. Also, note that for "pen" they chose 12 cm even though real pens are 14–15 cm, so they accept slight underestimation.

Similarly, for lollipop, 10 cm might be accepted as the stick length, ignoring the candy? But the line includes the candy.

Perhaps the intended answer is A. 10 centimeters.

I recall that in some worksheets, lollipop is listed as 10 cm. So I'll go with that.

Final decision for 5: A. 10 centimeters

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Now compiling all answers:

1) D
2) C
3) D
4) B
5) A
6) A
7) C
8) C
9) A

Let me verify once more:

1) Bug: 7 mm — yes
2) Battery: 5 cm — yes
3) Dresser: 90 cm — yes
4) Fridge: 180 cm — yes
5) Lollipop: 10 cm — acceptable
6) Can of beans: 10 cm — yes
7) Toothbrush: 17 cm — yes
8) Pen: 12 cm — acceptable (some pens are this short)
9) Ferris wheel: 23 m — yes for small one

All seem reasonable.

Final Answer:
1) D
2) C
3) D
4) B
5) A
6) A
7) C
8) C
9) A