Let’s solve each problem one by one.
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Problem 1:
Fair Bluff population: 9.8 × 10⁴
Tabor City population: 2.5 × 10⁴
To find how many times larger Fair Bluff is than Tabor City, divide the two numbers:
(9.8 × 10⁴) ÷ (2.5 × 10⁴) = (9.8 ÷ 2.5) × (10⁴ ÷ 10⁴) = 3.92 × 1 =
3.92
Since the question says “about”, we can round to about
4 times larger.
✔ Check: 2.5 × 4 = 10 → close to 9.8 — makes sense.
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Problem 2:
Virus diameter: 2.0 × 10⁻⁸ mm
Bacteria diameter: 2.0 × 10⁻⁶ mm
We want to compare bacteria size to virus size → divide bacteria by virus:
(2.0 × 10⁻⁶) ÷ (2.0 × 10⁻⁸) = (2.0 ÷ 2.0) × (10⁻⁶ ÷ 10⁻⁸) = 1 × 10² =
100
So the bacteria is
100 times larger than the virus.
Looking at options:
a) about 10 times smaller → no
b) about 10 times larger → no
c) about 100 times smaller → no
d) about 100 times larger →
✔ YES
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Problem 3:
Red panda weight: 5.0 × 10³ grams
Giant panda weight: 1.5 × 10⁵ grams
Divide giant panda by red panda:
(1.5 × 10⁵) ÷ (5.0 × 10³) = (1.5 ÷ 5.0) × (10⁵ ÷ 10³) = 0.3 × 10² = 30
So the giant panda is
30 times larger.
✔ Check: 5.0 × 10³ = 5,000; 1.5 × 10⁵ = 150,000 → 150,000 ÷ 5,000 = 30 — correct.
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Problem 4:
Speed of light: 3.0 × 10⁸ m/s
Speed of sound: 3.0 × 10² m/s
Divide speed of light by speed of sound:
(3.0 × 10⁸) ÷ (3.0 × 10²) = (3.0 ÷ 3.0) × (10⁸ 10²) = 1 × 10⁶ =
1,000,000
So light is
1 million times faster than sound.
✔ Check: 10⁸ 10² = 10⁶ — yes.
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Final Answers:
1. About 4 times larger
2. d) about 100 times larger
3. About 30 times larger
4. About 1,000,000 times faster
Parent Tip: Review the logic above to help your child master the concept of scientific notation word problems worksheet.