Page 121 - Mathematics_Std_4

Example 2

1 × 1 =
3 4
FOR ONLINE READING ONLY
Solution

Multiply the numerator by the numerator and the denominator
by the denominator:
×
1 × 1 = 11 = 1
3 4 3 × 4 12

1 1 1
Therefore, × = .
3 4 12

Alternative method: Multiplication by using rectangular
diagrams

Multiplication of fractions by fractions can be done using
rectangular diagrams as follows.

Steps

1. Draw three horizontal rectangles and four vertical
rectangles in the larger rectangle.
1 1
2. Shade the rectangles vertically and horizontally.
4 3
3. Count the number of squares that have been shaded
twice: you get 1 square which is the numerator.

4. The total number of squares, both shaded and unshaded,
is 12, which is the denominator.

Therefore, 1 × 1 = 1
3 4 12

114

06/11/2024 17:17:34
MATHEMATICS STD 4 PB 2024.indd 114
MATHEMATICS STD 4 PB 2024.indd 114 06/11/2024 17:17:34