Number System

Chapter 1

NUMBER SYSTEM

Learning Objectives

● To know the rounding of decimal numbers.

● To understand the four fundamental operations on decimal numbers.

Recap-Decimal numbers

We have studied about decimal numbers in the previous term. Let us recall them now by answering the following questions.

Try these

1. Represent the fraction 1/4 in decimal form.

Solution:

1/4 = [1 × 25] / [4 × 25] = 25 / 100 = 0.25

2. What is the place value of 5 in 63.257.

Solution:

Place value of 5 in 63.257 is 5 hundredths (Hundreth place)

3. Identify the digit in the tenth place of 75.036.

Solution:  0

4. Express the decimal number 3.75 as a fraction.

Solution:  3.75 = 375 / 100 = 15 / 4 

5. Write the decimal number for the fraction 5 (1/5).

Solution:  5( 1/5) = 26 / 5 = [ 26 × 2 ] / [ 5 × 2 ] = 52 / 10 = 5.2

6. Identify the bigger number : 0.567 or 0.576.

Solution:  Comparing the digits of 0.567 and 0.576 from left to right, we have the tenths place same comparing the hundredths place 7 > 6.

=> 0.576 > 0.567

7. Compare 3.30 and 3.03 and identify the smaller number.

Solution:  The whole number is equal in both the numbers.

Now comparing the tenths place we have 3 > 0

=> 3.03 < 3,30 Smaller number is 3.03

8. Put the appropriate sign (<, >, =). 2.57 ___ 2.570

Solution:  2.57 = 2.570

9. Arrange the following decimal numbers in ascending order. 5.14, 5.41, 1.54, 1.45, 4.15, 4.51.

Solution:  Comparing the numbers from left to right. Ascending order : 1.45, 1.54. 4.15, 4.51, 5.14, 5.41

Introduction

Mani went to market to purchase vegetables. The price details of five different vegetables on that day are shown in the following table.

● Mani wanted to round of each price to the nearest rupees.

● How will you decide on rounding each number?