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ML Aggarwal Class 8 Solutions for ICSE Maths Chapter 3 Squares and Square Roots Ex 3.2

Question 1.
Write five numbers which you can decide by looking at their one’s digit that they are not square numbers.
Solution:

Question 2.
What will be the unit digit of the squares of the following numbers?
(i) 951
(ii) 502
(iii) 329
(iv) 643
(v) 5124
(vi) 7625
(vii) 68327
(viii) 95628
(ix) 99880
(x) 12796
Solution:

Question 3.
The following numbers are obviously not perfect. Give reason.
(i) 567
(ii) 2453
(iii) 5298
(iv) 46292
(v) 74000
Solution:

Question 4.
The square of which of the following numbers would be an odd number or an even number? Why?
(i) 573
(ii) 4096
(iii) 8267
(iv) 37916
Solution:

Question 5.
How many natural numbers lie between the square of the following numbers?
(i) 12 and 13
(ii) 90 and 91
Solution:

Question 6.
Without adding, find the sum.
(i) 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15
(ii) 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19 + 21 + 23 + 25 + 27 + 29
Solution:

Question 7.
(i) Express 64 as the sum of 8 odd numbers.
(ii) 121 as the sum of 11 odd numbers.
Solution:

Question 8.
Express the following as the sum of two consecutive integers:
(i) 19²
(ii) 33²
(iii) 47²
Solution:

Question 9.
Find the squares of the following numbers without actual multiplication:
(i) 31
(ii) 42
(iii) 86
(iv) 94
Solution:

Question 10.
Find the squares of the following numbers containing 5 in unit’s place:
(i) 45
(ii) 305
(iii) 525
Solution:

Question 11.
Write a Pythagorean triplet whose one number is
(i) 8
(ii) 15
(iii) 63
(iv) 80
Solution:

Question 12.
Observe the following pattern and find the missing digits:
21² = 441
201² = 40401
2001² = 4004001
20001² = 4 – – – 4 – – – 1
200001² = ————–
Solution:

Question 13.
Observe the following pattern and find the missing digits:
9² = 81
99² = 9801
999² = 998001
9999² = 99980001
99999² = 9——–8———01
999999² = 9——–0———1
Solution:

Question 14.
Observe the following pattern and find the missing digits:
7² = 49
67² = 4489
667² = 444889
6667² = 44448889
66667² = 4 ———–8 ————– 9
666667² = 4———–8————8 –
Solution:

ML Aggarwal Class 8 Solutions for ICSE Maths

ML Aggarwal Class 8 Solutions for ICSE Maths Chapter 3 Squares and Square Roots Ex 3.1

Question 1.
Which of the following natural numbers are perfect squares? Give reasons in support of your answer.
(i) 729
(ii) 5488
(iii) 1024
(iv) 243
Solution:

Question 2.
Show that each of the following numbers is a perfect square. Also, find the number whose square is the given number.
(i) 1296
(ii) 1764
(iii) 3025
(iv) 3969
Solution:

Question 3.
Find the smallest natural number by which 1008 should be multiplied to make it a perfect square.
Solution:

Question 4.
Find the smallest natural number by which 5808 should be divided to make it a perfect square. Also, find the number whose square is the resulting number.
Solution:

ML Aggarwal Class 8 Solutions for ICSE Maths

ML Aggarwal Class 8 Solutions for ICSE Maths Chapter 2 Exponents and Powers Check Your Progress

Question 1.
Evaluate:

Solution:

Question 2.
Simplify:

Solution:

Question 3.
Find the multiplicative inverse of \(\left(\frac{125}{27}\right)^{\frac{-2}{3}}\)
Solution:

Question 4.
Simplify and write in exponential form:

Solution:

Question 5.
Simplify: \(\frac{5^{n+2}-6+5^{n+1}}{13 \times 5^{n}-2 \times 5^{n+1}}\)
Solution:

Question 6.
Prove that (a + b)^-1 (a^-1 + b^-1) = (ab)^-1.
Solution:

Question 7.
Find the value of x for which

Solution:

Question 8.
If \(\frac{2^{-n} \times 8^{2 n+1} \times 16^{2 n}}{4^{3 n}}=\frac{1}{16}\), find the value of n.
Solution:

Question 9.
By what number should \(\left[\left(\frac{-5}{2}\right)^{3}\right]^{-3}\) be multiplied to get \(\left(\frac{-2}{5}\right)^{5}\)?
Solution:

Question 10.
By what number should \(\left(\frac{-3}{2}\right)^{-4}\) be divided to get \(\left(\frac{-2}{3}\right)^{3}\)?
Solution:

Question 11.
Express the following numbers in standard form:
(i) 0.0000000003904
(ii) 12730000000000
Solution:

Question 12.
Express the following numbers in the usual form:
(i) 5.73 × 10^-11
(ii) 3.895 × 10¹⁵.
Solution:

Question 13.
If \(\left(\frac{9}{4}\right)^{-4} \times\left(\frac{2}{3}\right)^{3}=\left(\frac{p}{q}\right)^{11}\), then find the value of \(\left(\frac{p}{q}\right)^{-2}\).
Solution:

Question 14.
Mass of the Earth is 5.97 × 10²⁴ kg and mass of the Moon is 7.35 × 10²² kg. What is the difference of their masses?
Solution:

ML Aggarwal Class 8 Solutions for ICSE Maths

ML Aggarwal Class 8 Solutions for ICSE Maths Chapter 2 Exponents and Powers Objective Type Questions

Mental Maths

Question 1.
Fill in the blanks:
(i) Multiplicative inverse of \(\left( \frac { -4 }{ 5 } \right) ^{ 2 }\) = ……..
(ii) The standard form of 0.000182 = ………
(iii) The standard form of ……….. is 0.00000003572.
(iv) Expanded form of 273.92 = ………..
(v) If (-7)^x × \(\left( \frac { 1 }{ -7 } \right) ^{ -3 }\) = 7⁸, then value of x is …….
(vi) If 3ⁿ = 729, then n = ……
(vii) The value of (7⁰ + 5⁰) is ……..
Solution:

Question 2.
State whether the following statements are true (T) or false (F):
(i) The value of (-3)^-2 is \(\frac { 1 }{ -9 }\).
(ii) For negative integers m and n, a^m × aⁿ = a^m+n (a ≠ 0).
(iii) 3⁰ × 4⁰ = 12⁰.
(iv) The value of 3⁷ – 2⁷ is 1⁷.
(v) The standard form of 0.0034 is 3.4 × 10³.
(vi) Multiplicative inverse of (-2)⁵ is \(\frac { 1 }{ -32 }\).
Solution:

Multiple Choice Questions

Choose the correct answer from the given four options (3 to 12):
Question 3.
\(\left( \frac { 1 }{ 2 } \right) ^{ -5 }\) is equal to
(a) 32
(b) \(\frac { 1 }{ 32 }\)
(c) -32
(d) \(\frac { -1 }{ 32 }\)
Solution:

Question 4.

Solution:

Question 5.
If 2⁴ × 4³ = 4^x, then the value of x is
(a) 5
(b) 7
(c) 4
(d) -5
Solution:

Question 6.

Solution:

Question 7.

Solution:

Question 8.
Standard form of 0.000000789 is
(a) 78.9 × 10^-8
(b) 789 × 10^-9
(c) 7.89 × 10^-7
(d) None
Solution:

Question 9.
The usual form of 3.67 × 10⁵ is
(a) 3670000
(b) 367000
(c) 36700
(d) 3670
Solution:

Question 10.
Multiplicative inverse of \(\left( \frac { -2 }{ 3 } \right) ^{ 4 }\) is
(a) \(\frac { 16 }{ 81 }\)
(b) \(\frac { -16 }{ 81 }\)
(c) \(\frac { 81 }{ 16 }\)
(d) \(\frac { -81 }{ 16 }\)
Solution:

Question 11.

Solution:

Question 12.

Solution:

Value Based Questions

Question 1.
Anaemia causes due to deficiency of Red Blood cells. The size of a red blood cell is 0.000000007 mm. Express it in standard form. Rahul is suffering from anemia, his doctor adviced him to take healthy food regularly and avoid junk food.
Why should we eat healthy food? What values are being promoted?
Solution:

Higher Order Thinking Skills (HOTS)

Question 1.
Find the multiplicative inverse of (5⁰ + 3⁰) (5⁰ – 3⁰).
Solution:

Question 2.

Solution:

Question 3.

Solution:

ML Aggarwal Class 8 Solutions for ICSE Maths

ML Aggarwal Class 8 Solutions for ICSE Maths Chapter 2 Exponents and Powers Ex 2.2

Question 1.
Express the following numbers in standard form:
(i) 0.0000000000085
(ii) 0.000000000000942
(iii) 6020000000000000
(iv) 0.00000000837
Solution:

Question 2.
Express the following numbers in the usual form:
(i) 3.02 × 10^-6
(ii) 1-007 × 10¹¹
(iii) 5.375 × 10¹⁴
(iv) 7.579 × 10^-14
Solution:

Question 3.
Express the number appearing in the following statements in standard form:
(i) The mass of a proton is 0.000000000000000000000001673 gram.
(ii) The thickness of a piece of paper is 0.0016 cm.
(iii) The diameter of a wire on a computer chip is 0.000003 m.
(iv) A helium atom has a diameter of \(\frac { 22 }{ 100000000000 }\) m
(v) Mass of a molecule of hydrogen gas is about 0.00000000000000000000334 tons.
(vi) The human body has 1 trillion cells which vary in shapes and sizes.
(vii) The distance from the Earth of the Sun is 149,600,000,000 m.
(viii) The speed of light is 300,000,000 m/sec.
(ix) Mass of the Earth is 5,970,000,000,000,000,000,000,000 kg.
(x) Express 3 years in seconds.
(xi) Express 7 hectares in cm².
(xii) A sugar factory has annual sales of 3 billion 720 million kilograms of sugar.
Solution:

Question 4.
Compare the following:
(i) Size of a plant cell to the thickness of a piece of paper.
(ii) Size of a plant cell to the diameter of a wire on a computer chip.
(iii) The thickness of a piece of paper to the diameter of a wire on a computer chip.
Given size of plant cell = 0.00001275 m
Thickness of a piece of paper = 0.0016 cm
Diameter of a wire on a computer chip = 0.000003 m
Solution:

Question 5.
The number of red blood cells per cubic millimetre of blood is approximately 5.5 million. If the average body contains 5 litres of blood, what is the total number of red cell in the body? (1 litre = 1,00,000 mm³)
Solution:

Question 6.
Mass of Mars is 6.42 × 10²⁹ kg and the mass of the sun is 1.99 × 10³⁰ kg. What is the total mass?
Solution:

Question 7.
A particular star is at a distance of about 8.1 × 10¹³ km from the Earth. Assuming that the light travels at 3 × 10⁸ m/sec, find how long does light take from that star to reach the Earth.
Solution:

ML Aggarwal Class 8 Solutions for ICSE Maths