Question 21 of 58beginner🔧 ApplyDiagram2 marks

Try and represent 85\frac{8}{5} and −74-\frac{7}{4} on a number line.

Correct Answer

To represent 85\frac{8}{5} and −74-\frac{7}{4} on the number line, we first convert them into mixed fractions to determine the integers between which they lie. We have 85=135\frac{8}{5} = 1\frac{3}{5}, which lies between 1 and 2. Also, −74=−134-\frac{7}{4} = -1\frac{3}{4}, which lies between -2 and -1. To represent 85\frac{8}{5}, we divide the unit intervals on the number line into 5 equal parts each. We then move 8 parts to the right of 0 (or 3 parts to the right of 1) to mark the point.

To represent −74-\frac{7}{4}, we divide the unit intervals into 4 equal parts each. We then move 7 parts to the left of 0 (or 3 parts to the left of -1) to mark the point.

Exercise: Think and Reflect | Q: 1 | (Page 11)
For More Understanding

Explanation

The textbook explains that to represent a rational number p/q on the number line, one must divide the unit interval (distance between consecutive integers) into q equal parts. For positive numbers, we move p parts to the right of 0, and for negative numbers, we move p parts to the left. Converting improper fractions to mixed fractions (like 9/4 = 2 1/4 in the text) helps identify the specific integer interval where the point lies, making it easier to draw and label the number line accurately.

Solution Steps

  1. Step 1: Convert the rational numbers to mixed fractions: 85=135\frac{8}{5} = 1\frac{3}{5} (lies between 1 and 2) and −74=−134-\frac{7}{4} = -1\frac{3}{4} (lies between -2 and -1).

  2. Step 2: For 85\frac{8}{5}, divide the intervals between 0, 1, and 2 into 5 equal parts. Move 8 parts to the right of 0 (or 3 parts right of 1).

  3. Step 3: For −74-\frac{7}{4}, divide the intervals between -2, -1, and 0 into 4 equal parts. Move 7 parts to the left of 0 (or 3 parts left of -1).