Math practice sheet containing exercises on exponents, powers, and converting large numbers into standard form.
Math worksheet featuring exponent rules and scientific notation problems numbered 23 to 40.
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Step-by-step solution for: Class 7 Important Questions for Maths - Exponents and Powers ...
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Show Answer Key & Explanations
Step-by-step solution for: Class 7 Important Questions for Maths - Exponents and Powers ...
Let’s go through each problem one by one, solving them step by step and checking our work carefully.
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23. (–2)³¹ × (–2)¹³ = (–2)___
When multiplying powers with the same base, we add the exponents:
(–2)³¹ × (–2)¹³ = (–2)^(31 + 13) = (–2)^44
✔ Final answer for 23: 44
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24. (–3)⁸ ÷ (–3)⁵ = (–3)___
When dividing powers with the same base, subtract the exponents:
(–3)⁸ ÷ (–3)⁵ = (–3)^(8 – 5) = (–3)^3
✔ Final answer for 24: 3
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25. (11/15)⁴ × (___)⁵ = (11/15)⁹
We know that (11/15)⁴ × (11/15)⁵ = (11/15)^(4+5) = (11/15)⁹
So the blank must be (11/15)
✔ Final answer for 25: 11/15
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26. (–1/4)³ × (–1/4)^__ = (–1/4)¹¹
Add exponents: 3 + x = 11 → x = 8
✔ Final answer for 26: 8
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27. [(7/11)³]⁴ = (7/11)^__
Power of a power: multiply exponents → 3 × 4 = 12
✔ Final answer for 27: 12
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28. (6/13)¹⁰ ÷ [(6/13)⁵]² = (6/13)^__
First simplify denominator: [(6/13)⁵]² = (6/13)^(5×2) = (6/13)^10
Then: (6/13)¹⁰ ÷ (6/13)¹⁰ = (6/13)^(10–10) = (6/13)^0
✔ Final answer for 28: 0
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29. [(–1/4)¹⁶]² = (–1/4)^__
Power of a power: 16 × 2 = 32
✔ Final answer for 29: 32
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30. (13/14)⁵ ÷ (__)² = (13/14)³
Let the blank be x.
So: (13/14)⁵ ÷ x² = (13/14)³
→ x² = (13/14)⁵ ÷ (13/14)³ = (13/14)^(5–3) = (13/14)²
So x = 13/14
✔ Final answer for 30: 13/14
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31. a⁶ × a⁵ × a⁰ = a^__
Add exponents: 6 + 5 + 0 = 11
Note: a⁰ = 1, so it doesn’t change the product.
✔ Final answer for 31: 11
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32. 1 lakh = 10^__
1 lakh = 100,000 = 10⁵
✔ Final answer for 32: 5
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33. 1 million = 10^__
1 million = 1,000,000 = 10⁶
✔ Final answer for 33: 6
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34. 729 = 3^__
Try powers of 3:
3¹ = 3
3² = 9
3³ = 27
3⁴ = 81
3⁵ = 243
3⁶ = 729 ✔
✔ Final answer for 34: 6
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35. 432 = 2⁴ × 3^__
First, 2⁴ = 16
432 ÷ 16 = 27
27 = 3³
So 432 = 2⁴ × 3³
✔ Final answer for 35: 3
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36. 537000000 = __ × 10⁷
Count digits after first digit: 537000000 has 8 digits after 5? Wait — let’s write it as:
537,000,000 = 5.37 × 100,000,000 = 5.37 × 10⁸? But question says × 10⁷.
Wait — 537000000 ÷ 10⁷ = 537000000 ÷ 10000000 = 53.7
So 537000000 = 53.7 × 10⁷
But usually we use scientific notation with one digit before decimal — but the question just asks for “__ × 10⁷”, so 53.7 is correct.
Alternatively, maybe they want integer? Let’s check:
10⁷ = 10,000,000
537,000,000 ÷ 10,000,000 = 53.7
Yes, so answer is 53.7
✔ Final answer for 36: 53.7
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37. 888800000000 = __ × 10¹⁰
10¹⁰ = 10,000,000,000
888,800,000,000 ÷ 10,000,000,000 = 88.88
So 888800000000 = 88.88 × 10¹⁰
✔ Final answer for 37: 88.88
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38. 27500000 = 2.75 × 10^__
Move decimal point in 2.75 to get 27500000:
2.75 → 27.5 → 275 → 2750 → 27500 → 275000 → 2750000 → 27500000 → that’s 7 moves.
So 2.75 × 10⁷ = 27,500,000 ✔
✔ Final answer for 38: 7
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39. 340900000 = 3.409 × 10^__
Move decimal from 3.409 to 340900000:
3.409 → 34.09 → 340.9 → 3409 → 34090 → 340900 → 3409000 → 34090000 → 340900000 → 8 moves.
So 3.409 × 10⁸ = 340,900,000 ✔
✔ Final answer for 39: 8
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40. Fill in blanks with <, > or =
(a) 3² ___ 15
3² = 9 → 9 < 15 → <
(b) 2³ ___ 3²
2³ = 8, 3² = 9 → 8 < 9 → <
(c) 7⁴ ___ 5⁴
Same exponent, bigger base → 7⁴ > 5⁴ → >
(d) 10,000 ___ 10⁵
10,000 = 10⁴, 10⁵ = 100,000 → 10⁴ < 10⁵ → <
(e) 6³ ___ 4⁴
6³ = 216
4⁴ = 256
216 < 256 → <
✔ Final answers for 40:
(a) <
(b) <
(c) >
(d) <
(e) <
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Final Answer:
23. 44
24. 3
25. 11/15
26. 8
27. 12
28. 0
29. 32
30. 13/14
31. 11
32. 5
33. 6
34. 6
35. 3
36. 53.7
37. 88.88
38. 7
39. 8
40. (a) < (b) < (c) > (d) < (e)
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23. (–2)³¹ × (–2)¹³ = (–2)___
When multiplying powers with the same base, we add the exponents:
(–2)³¹ × (–2)¹³ = (–2)^(31 + 13) = (–2)^44
✔ Final answer for 23: 44
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24. (–3)⁸ ÷ (–3)⁵ = (–3)___
When dividing powers with the same base, subtract the exponents:
(–3)⁸ ÷ (–3)⁵ = (–3)^(8 – 5) = (–3)^3
✔ Final answer for 24: 3
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25. (11/15)⁴ × (___)⁵ = (11/15)⁹
We know that (11/15)⁴ × (11/15)⁵ = (11/15)^(4+5) = (11/15)⁹
So the blank must be (11/15)
✔ Final answer for 25: 11/15
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26. (–1/4)³ × (–1/4)^__ = (–1/4)¹¹
Add exponents: 3 + x = 11 → x = 8
✔ Final answer for 26: 8
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27. [(7/11)³]⁴ = (7/11)^__
Power of a power: multiply exponents → 3 × 4 = 12
✔ Final answer for 27: 12
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28. (6/13)¹⁰ ÷ [(6/13)⁵]² = (6/13)^__
First simplify denominator: [(6/13)⁵]² = (6/13)^(5×2) = (6/13)^10
Then: (6/13)¹⁰ ÷ (6/13)¹⁰ = (6/13)^(10–10) = (6/13)^0
✔ Final answer for 28: 0
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29. [(–1/4)¹⁶]² = (–1/4)^__
Power of a power: 16 × 2 = 32
✔ Final answer for 29: 32
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30. (13/14)⁵ ÷ (__)² = (13/14)³
Let the blank be x.
So: (13/14)⁵ ÷ x² = (13/14)³
→ x² = (13/14)⁵ ÷ (13/14)³ = (13/14)^(5–3) = (13/14)²
So x = 13/14
✔ Final answer for 30: 13/14
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31. a⁶ × a⁵ × a⁰ = a^__
Add exponents: 6 + 5 + 0 = 11
Note: a⁰ = 1, so it doesn’t change the product.
✔ Final answer for 31: 11
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32. 1 lakh = 10^__
1 lakh = 100,000 = 10⁵
✔ Final answer for 32: 5
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33. 1 million = 10^__
1 million = 1,000,000 = 10⁶
✔ Final answer for 33: 6
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34. 729 = 3^__
Try powers of 3:
3¹ = 3
3² = 9
3³ = 27
3⁴ = 81
3⁵ = 243
3⁶ = 729 ✔
✔ Final answer for 34: 6
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35. 432 = 2⁴ × 3^__
First, 2⁴ = 16
432 ÷ 16 = 27
27 = 3³
So 432 = 2⁴ × 3³
✔ Final answer for 35: 3
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36. 537000000 = __ × 10⁷
Count digits after first digit: 537000000 has 8 digits after 5? Wait — let’s write it as:
537,000,000 = 5.37 × 100,000,000 = 5.37 × 10⁸? But question says × 10⁷.
Wait — 537000000 ÷ 10⁷ = 537000000 ÷ 10000000 = 53.7
So 537000000 = 53.7 × 10⁷
But usually we use scientific notation with one digit before decimal — but the question just asks for “__ × 10⁷”, so 53.7 is correct.
Alternatively, maybe they want integer? Let’s check:
10⁷ = 10,000,000
537,000,000 ÷ 10,000,000 = 53.7
Yes, so answer is 53.7
✔ Final answer for 36: 53.7
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37. 888800000000 = __ × 10¹⁰
10¹⁰ = 10,000,000,000
888,800,000,000 ÷ 10,000,000,000 = 88.88
So 888800000000 = 88.88 × 10¹⁰
✔ Final answer for 37: 88.88
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38. 27500000 = 2.75 × 10^__
Move decimal point in 2.75 to get 27500000:
2.75 → 27.5 → 275 → 2750 → 27500 → 275000 → 2750000 → 27500000 → that’s 7 moves.
So 2.75 × 10⁷ = 27,500,000 ✔
✔ Final answer for 38: 7
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39. 340900000 = 3.409 × 10^__
Move decimal from 3.409 to 340900000:
3.409 → 34.09 → 340.9 → 3409 → 34090 → 340900 → 3409000 → 34090000 → 340900000 → 8 moves.
So 3.409 × 10⁸ = 340,900,000 ✔
✔ Final answer for 39: 8
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40. Fill in blanks with <, > or =
(a) 3² ___ 15
3² = 9 → 9 < 15 → <
(b) 2³ ___ 3²
2³ = 8, 3² = 9 → 8 < 9 → <
(c) 7⁴ ___ 5⁴
Same exponent, bigger base → 7⁴ > 5⁴ → >
(d) 10,000 ___ 10⁵
10,000 = 10⁴, 10⁵ = 100,000 → 10⁴ < 10⁵ → <
(e) 6³ ___ 4⁴
6³ = 216
4⁴ = 256
216 < 256 → <
✔ Final answers for 40:
(a) <
(b) <
(c) >
(d) <
(e) <
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Final Answer:
23. 44
24. 3
25. 11/15
26. 8
27. 12
28. 0
29. 32
30. 13/14
31. 11
32. 5
33. 6
34. 6
35. 3
36. 53.7
37. 88.88
38. 7
39. 8
40. (a) < (b) < (c) > (d) < (e)
Parent Tip: Review the logic above to help your child master the concept of powers and exponents worksheet pdf.