Class 8 Maths
Exponents and Powers
Ex.12.1 Q.1
Evaluate:
1. 3-2
2. (-4)-2
3. ( )-5
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Ex.12.1 Q.2
Simplify and express the result in power notation with positive exponent:
1. (-4)5 ÷ (-4)8
2. (1 ÷ 23)2
3. (-3)4 × (5 ÷ 3)4
4. (3-7 × 3-10) × 35
5. 2-3 × (-7)3
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Ex.12.1 Q.3
Find the value of:
1. (30 + 4-1) × 22
2. (2-1 × 4-1) ÷ 2-2
3. (1 ÷ 2)-2 + (1 ÷ 3)-2 + (1 ÷ 4)-2
4. (3-1 + 4-1 + 5-1)0
5. {(-2 ÷ 3)-2}2
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Ex.12.1 Q.4
Evaluate:
1. (8-1 × 53) ÷ 2-4
2. (5-1 × 2-1) × 6-1
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Ex.12.1 Q.5
Find the value of m for which 5m ÷ 5-3 = 55
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Ex.12.1 Q.6
Evaluate:
1. {(1 ÷ 3)-1 + (1 ÷ 4)-1}-1
2. (5 ÷ 8)-7 × (8 ÷ 5)-4
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Ex.12.1 Q.7
Simplify:
1. (25 × t-4) ÷ (5-3 × 10 × t-8)
(t ≠ 0)
2. (3-5 × 10-5 × 125) ÷ (5-7 × 6-5)
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Ex.12.2 Q.1
Express the following numbers in standard form:
1. 0.0000000000085
2. 0.00000000000942
3. 6020000000000000
4. 0.00000000837
5. 31860000000
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Ex.12.2 Q.2
Express the following numbers in usual form:
1. 3.02 × 10-6
2. 4.5 × 104
3. 3 × 10-8
4. 1.0001 × 109
5. 5.8 × 1012
6. 3.61492 × 106
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Ex.12.2 Q.3
Express the number appearing in the following statements in standard form:
1. 1 micron is equal to m.
2. Charge of an electron is 0.000,000,000,000,000,000,16 coulomb.
3. Size of a bacteria is 0.0000005 m.
4. Size of a plant cell is 0.00001275 m.
5. Thickness if a thick paper is 0.07 mm.
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Ex.12.2 Q.4
In a stack there are 5 books each of thickness 20 mm and 5 paper sheets each of thickness 0.016 mm.
What is the total thickness of the stack?
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