Students can Download Class 7 Maths Chapter 13 Exponents and Powers Ex 13.3 Questions and Answers, Notes Pdf, KSEEB Solutions for Class 7 Maths helps you to revise the complete Karnataka State Board Syllabus and to clear all their doubts, score well in final exams.

## Karnataka State Syllabus Class 7 Maths Chapter 13 Exponents and Powers Ex 13.3

Question 1.

Write the following numbers in the expanded forms:

279404, 3006194, 2806196, 120719, 20068.

Solution:

279404 = 2 × 10^{5} + 7 × 10^{4} + 9 × 10^{3} + 4 × 10^{2} + 0 × 10^{1} + 4 × 10^{0}

3006194 = 3 × 10^{6} + 0 × 10^{5} + 0 × 10^{4} + 6 × 10^{3} + 1 × 10^{2} + 9 × 10^{1} + 4 × 10^{0}

2806196 = 2 × 10^{6} + 8 × 10^{5} + 0 × 10^{4} + 6 × 10^{3}+ 1 × 10^{2} + 9 × 10^{3} + 6 × 10^{0}

120719 = 1 × 10^{5} + 2 × 10^{4} + 0 × 10^{3} + 7 × 10^{2} + 1 × 10^{1} + 9 × 10^{0}

20068 = 2 × 10^{4} + 0 × 10^{3} + 0 × 10^{2} + 6 × 10^{1} + 8 × 10^{0}

Question 2.

Find the number from each of the following expanded forms:

a. 8 × 10^{4} + 6 × 10^{3} + 0 × 10^{2} + 4 × 10^{1} + 5 × 10^{0}

b. 4 × 10^{5} + 5 × 10^{3} + 3 × 10^{2} + 2 × 10^{0}

c. 3 × 10^{4} + 7 × 10^{2} + 5 × 10^{0}

d. 9 × 10^{5} + 2 × 10^{2} + 3 × 10^{1}

Solution:

a. 86045

b. 405302

c. 30705

d. 900230

Question 3.

Express the following numbers in standard form:

(i) 5,00,00,000

(ii) 70,00,000

(iii) 3,18,65,00,000

(iv) 3,90,878

(v) 39087.8

(vi) 3908.78

Solution:

(i) 5,00,00,000 = 5 × 10^{7}

(ii) 70,00,000 = 7 × 10^{6}

(iii) 3,18,65,00,000 = 3.1865 × 10^{9}

(iv) 3,90,878 = 3.90878 × 10^{5}

(v) 39087.8 = 3.90878 × 10^{4}

(vi) 3908.78 = 3,90878 × 10^{3}

Question 4.

Express the number appearing in the following statements in standard form.

(a) The distance between Earth and Moon is 384,000,000 m.

Solution:

3.84 × 10^{8}m

(b) Speed of light in vacuum is 300,000,000 m/s.

Solution:

3 × 10^{8}m/s

(c) Diameter of the Earth is 1,27,56,000 m.

Solution:

1.2756 × 10^{7}m

(d) Diameter of the Sun is 1,400,000,000 m.

Solution:

1.4 × 10^{9}m

(e) In a galaxy there are on an average 100,000,000,000 stars.

Solution:

1 × 10^{11}

(f) The universe is estimated to be about 12,000,000,000 years old.

Solution:

1.2 × 10^{10} years.

(g) The distance of the Sun from the centre of the Milky Way Galaxy is estimated to be 300,000,000, 000,000,000,000 m.

Solution:

3 × 10^{20}m.

(h) 60,230,000,000,000,000,000,000 molecules are contained in a drop of water weighing 1.8 gm.

Solution:

6.023 × 10^{22}

(i) The earth has 1,353,000,000 cubic km of sea water.

Solution:

1.353 × 10^{9} cubic km.

(j) The population of India was about 1,027,000,000 in March, 2001.

Solution:

1.027 × 10^{9}.