Sure! Let’s solve each problem step by step and express the final answer in
scientific notation.
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Problem 1:
(7 × 10⁴)(2 × 10⁶)
Multiply coefficients:
7 × 2 =
14
Add exponents (since same base 10):
10⁴ × 10⁶ = 10⁽⁴⁺⁶⁾ =
10¹⁰
So: 14 × 10¹⁰
But scientific notation requires coefficient between 1 and 10 → convert 14 to 1.4 × 10¹
→ 1.4 × 10¹ × 10¹⁰ =
1.4 × 10¹¹
✔ Answer: 1.4 × 10¹¹
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Problem 2:
(9 × 10⁵) + (5 × 10⁵)
Same exponent → add coefficients:
9 + 5 =
14
→ 14 × 10⁵
Convert to scientific notation:
14 = 1.4 × 10¹ → 1.4 × 10¹ × 10⁵ =
1.4 × 10⁶
✔ Answer: 1.4 × 10⁶
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Problem 3:
(3 × 10⁸) − (7 × 10⁷)
Exponents are different → make them same.
Convert 7 × 10⁷ to match 10⁸:
7 × 10⁷ = 0.7 × 10⁸
Now subtract:
3 × 10⁸ − 0.7 × 10⁸ = (3 − 0.7) × 10⁸ =
2.3 × 10⁸
✔ Answer: 2.3 × 10⁸
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Problem 4:
(5 × 10⁸) / (4 × 10³)
Divide coefficients:
5 ÷ 4 =
1.25
Subtract exponents:
10⁸ ÷ 10³ = 10⁽⁸⁻³⁾ =
10⁵
→
1.25 × 10⁵
✔ Answer: 1.25 × 10⁵
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Problem 5:
(2 × 10⁴) / (8 × 10²)
Divide coefficients:
2 ÷ 8 =
0.25
Subtract exponents:
10⁴ ÷ 10² = 10²
→ 0.25 × 10²
Convert to scientific notation:
0.25 = 2.5 × 10⁻¹ → 2.5 × 10⁻¹ × 10² =
2.5 × 10¹
✔ Answer: 2.5 × 10¹
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Problem 6:
(2 × 10⁷) − (4 × 10⁷)
Same exponent → subtract coefficients:
2 − 4 =
-2
→ -2 × 10⁷
Already in scientific notation (coefficient between 1 and 10 in absolute value).
✔ Answer: -2 × 10⁷
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Problem 7:
(6 × 10⁴) + (1 × 10⁵)
Different exponents → convert to same power.
1 × 10⁵ = 10 × 10⁴
Now:
6 × 10⁴ + 10 × 10⁴ = (6 + 10) × 10⁴ =
16 × 10⁴
Convert: 16 = 1.6 × 10¹ → 1.6 × 10¹ × 10⁴ =
1.6 × 10⁵
✔ Answer: 1.6 × 10⁵
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Problem 8:
(8 × 10⁵)(6 × 10⁷)
Multiply coefficients:
8 × 6 =
48
Add exponents:
10⁵ × 10⁷ = 10¹²
→ 48 × 10¹²
Convert: 48 = 4.8 × 10¹ → 4.8 × 10¹ × 10¹² =
4.8 × 10¹³
✔ Answer: 4.8 × 10¹³
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Problem 9:
(4 × 10⁹)(9 × 10⁵)
Multiply coefficients:
4 × 9 =
36
Add exponents:
10⁹ × 10⁵ = 10¹⁴
→ 36 × 10¹⁴
Convert: 36 = 3.6 × 10¹ → 3.6 × 10¹ × 10¹⁴ =
3.6 × 10¹⁵
✔ Answer: 3.6 × 10¹⁵
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Problem 10:
(3 × 10⁵) + (7 × 10⁷)
Different exponents → convert smaller to match larger.
3 × 10⁵ = 0.03 × 10⁷
Now:
0.03 × 10⁷ + 7 × 10⁷ = (0.03 + 7) × 10⁷ =
7.03 × 10⁷
✔ Answer: 7.03 × 10⁷
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##
✔ Final Answers:
1)
1.4 × 10¹¹
2)
1.4 × 10⁶
3)
2.3 × 10⁸
4)
1.25 × 10⁵
5)
2.5 × 10¹
6)
-2 × 10⁷
7)
1.6 × 10⁵
8)
4.8 × 10¹³
9)
3.6 × 10¹⁵
10)
7.03 × 10⁷
Let me know if you’d like a printable version or step-by-step work shown for any specific problem!
Parent Tip: Review the logic above to help your child master the concept of exponents and scientific notation review worksheet.