Step-by-Step Examples: Multiply Decimals by Whole Numbers Using Grids

📚 Quick Study Guide

• 🔢 Multiplying decimals by whole numbers involves treating the decimal number as a whole number initially and then adjusting the decimal point in the final answer.
• ➗ Grids provide a visual representation, where each cell represents a hundredth (0.01) or a tenth (0.1), depending on the grid size.
• ✏️ When using grids, shade in the grid to represent the decimal number repeated the number of times indicated by the whole number.
• 🧮 Count the total shaded area to find the product. This area represents the answer to the multiplication problem.
• 📍 The number of decimal places in the product should be the same as the number of decimal places in the original decimal number.

Practice Quiz

1. What is $2.3 \times 3$ using a grid representation?
1. 4.6
2. 6.9
3. 2.6
4. 8.2
2. Using a grid, what is $1.5 \times 4$?
1. 5.0
2. 6.0
3. 4.5
4. 5.5
3. If each cell in a grid represents 0.01, how would you represent $0.25 \times 5$?
1. Shade 5 rows of 25 cells
2. Shade 25 rows of 5 cells
3. Shade 5 columns of 25 cells
4. Any of the above
4. What is the product of $0.8 \times 6$ using a grid?
1. 4.8
2. 5.6
3. 6.4
4. 7.2
5. How many cells would you shade to represent $1.2 \times 2$ on a grid where each cell represents 0.1?
1. 24
2. 12
3. 2
4. 4
6. What does each fully shaded row represent in a grid representing tenths when multiplying a decimal by a whole number?
1. 0.01
2. 1
3. 0.1
4. 10
7. What is $0.75 \times 4$ using a grid representation?
1. 2.0
2. 2.5
3. 3.0
4. 3.5