For multiplication of two decimal numbers, such as 0.4 × 0.2 = 0.08, an appropriate teaching-learning tool to explain the concept is

Correct option is D

S. Ans. (d)

Solution:
To explain the multiplication of two decimal numbers, such as 0.4 × 0.2 = 0.08, graph paper is the most appropriate teaching-learning tool. Here’s why:

• Graph paper allows the visualization of decimal numbers in a structured grid form.
• To represent 0.4, a grid with 10 × 10 squares can be shaded to show 4 columns out of 10 (40% or 0.4).
• Similarly, to represent 0.2, 2 rows out of 10 are shaded.
• The overlapping region between the shaded rows and columns corresponds to the product of 0.4 and 0.2, which is 0.08 (8 squares out of 100).

This method helps students understand the concept of decimal multiplication by relating it to area calculation, thereby making the concept concrete and easy to grasp.

Information Booster:

1. Dienes blocks are primarily used to teach place value, addition, subtraction, and understanding of numbers, not decimals specifically.
2. Number charts are helpful for basic arithmetic and identifying number patterns but are not ideal for illustrating decimal multiplication.
3. Counting stars (abacus) are useful for teaching basic counting, addition, and subtraction but lack the ability to represent overlapping areas, which is crucial for visualizing decimal multiplication.
4. Graph paper provides a clear and visual representation of decimals and their products, making it the most effective tool for this specific purpose.

Additional Information:

• Graph paper: Ideal for teaching fractional and decimal operations through visualization.
• Dienes block: Used in early mathematics to introduce number sense and place value.
• Number chart: Assists in skip counting, multiplication tables, and recognizing patterns in numbers.
• Abacus: Suitable for building a strong foundation in number manipulation and mental calculations.

Key Points to Remember:

• Multiplication of decimals can be conceptualized as finding the area of a rectangle.
• Graph paper aligns well with the concept of percentages and fractions.
• Visual tools enhance conceptual understanding and reduce the abstractness of decimal operations.