NCERT Solutions for Class 8 Maths Chapter 12 Exercise 12.2 in Hindi and English Medium updated for CBSE 2022-2023 session.

## 8th Maths Exercise 12.2 Solution in Hindi and English Medium

### Class 8 Maths Chapter 12 Exercise 12.2 Solution

Class VIII Mathematics NCERT book Ex. 12.2 Exponents and Powers in PDF file format free to download for academic year 2022-23. Get here not only PDF solution but the videos explanation also. In exercise 12.2 of class 8 mathematics questions we learn that how to write a too large or too small number in scientific notation. Every question of NCERT 8th math ex. 12.2 are properly explained step by step in explanation video.

Class: 8 | Mathematics |

Chapter: 12 | Exercise: 12.2 |

Topic Name: | Exponents and Powers |

Medium: | Hindi and English Medium |

Content Type: | Text and Videos Format |

#### Use of Exponents to Express the Numbers in the Standard Form

The speed of light is 300,000,000 m/sec. This number is quite big and it is uneasy to read, 8 pronounce and write. We can write this number as 3 x 10⁸ m/sec. Similarly, the number 0.0000009 may be written as 9⁻⁷.

**The diameter of the sun is (1.4 x 10⁹) m and the diameter of the earth is (1.2756 x 10⁷) m. show that the diameter of the sun is nearly 100 times the diameter of the earth.**

We have:

diameter of the sun/ diameter of the earth = (1.4 x 10⁹) /(1.2756 x 10⁷)

= (14000 x 100)/12756 = 100 (nearly)

So, (diameter of the sun) = 100 x (diameter of the earth)

##### Numbers in Standard Form

A number written as a x 10ᵇ (read as a times ten raised to the power of b) is said to be in standard form, if b is an integer and a is a decimal number such that 1 ≤ a < 10.

**Express each of the following numbers in standard form: (i) 6872 (ii) 140000 (iii) 15360000000**

We may write

(i) 6872 = 6.872 x 1000 = (6.872 x 10³)

(ii) 140000 = 14 x 10000 = (1.4 x 10 x 10⁴) = (1.4 x 10⁵)

(iii) 15360000000 = 1536 x 10000000 = (1.536 x 1000 x 10⁷)

= (1.536 x 103 x 10⁷) = (1.536 x 10¹⁰)

###### Rules of decimal point

If the number is less than 1, then the decimal point is moved to the right so that there remains only one digit on the left of the decimal.

The given number is written as the product of the number so obtained and (10)-n, where it is the number of place, the decimal point has been moved to the right.

**Why are exponents useful when working with very large or very small numbers?**

Computation with very large numbers is made easier with scientific notation. When a number is written in scientific notation, the exponent tells you if the term is a large or a small number. A positive exponent indicates a large number and a negative exponent indicates a small number that is between 0 and 1.

**How do you solve exponents without a calculator?**

Write a multiplication sign between each of the base numbers that you have just written. An exponent is a number being multiplied by itself a certain number of times, and this is what you are representing when you write the multiplication signs between base numbers. Multiply out your new equation.

**How do you express a large number in standard form?**

Write the first number 8.

Add a decimal point after it: 8.

Now count the number of digits after 8. There are 13 digits.

So, in standard form: 81 900 000 000 000 is 8.19 × 10¹³

**How do you find missing exponents?**

Find The Missing Exponent

Step 1: To find the missing exponent, we have to get the same base on both sides.

Step 2: Once we get the same base, exponents can be equated and we can find the value of the missing exponent.

### Is the exercise 12.2 is easier than 12.1 in chapter 12 of class 8 Maths NCERT?

If we compare both the exercises, we feel that the exercise 12.2 of chapter 12 exponents and powers from class 8 Mathematics is the easiest exercise. As this exercise contains only four simple questions. The size of the questions is overwhelming but solving them is much easier than the previous exercise 12.1.

### What is importance of exercise 12.2 class 8th Maths for final exams?

Exercise 12.2 of topic exponents and powers from grade 8 Maths carries questions which are frequently asked in exams. You will get the Evaluation questions in the exam from exercise 12.2. These questions are a quick and easy way to score well.

### What are the most important questions from exercise 12.2 of class 8 Maths?

Question number 2 express the various number and question number three expression of standard form is an easy and important too in exercise 12.2 from class 8 Maths NCERT. In exercise 12.2 of exponents and powers has evaluating questions and examples that are important.